Techniques of Bukhara Ancient Jewelry Art [1, 1 ed.]

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MAMUR FATAEV TECHNIQUES OF BUKHARA ANCIENT JEWELRY ART

TECHNIQUES OF BUKHARA ANCIENT JEWELRY ART History of Bukhara Jewelry Art: A Tapestry of Influences The history of Bukhara jewelry art is a fascinating journey through centuries, reflecting the city's rich cultural heritage and its position as a crossroads on the Silk Road. Here's a glimpse into its evolution: Early Influences: • Nomadic Tribes: Bukhara's earliest jewelry traditions likely originated from nomadic tribes who inhabited the region. They used natural materials like bones, shells, and turquoise to create simple yet symbolic pieces. • Zoroastrianism: This ancient religion emphasized the importance of fire, light, and

purity, influencing the use of gold and silver in jewelry. • Buddhism: With the arrival of Buddhism in the 2nd century BCE, floral motifs and

animal figures became incorporated into jewelry designs. Golden Age of Bukhara: • Samanid Dynasty (819-999 CE): This period marked a flourishing of Bukhara's

arts and crafts. Jewelry makers employed intricate techniques like granulation, filigree, and cloisonné enameling, creating pieces adorned with precious stones like turquoise, lapis lazuli, and carnelian. • Caravan Trade: The Silk Road brought Bukhara into contact with diverse

cultures, further enriching its jewelry styles. Influences from China, India, and Persia can be seen in the use of new materials, motifs, and techniques. Evolving Styles: • Timurid Dynasty (1370-1507 CE): Geometric patterns, inscriptions, and

calligraphy became more prominent, reflecting Islamic artistic traditions. • Emirate of Bukhara (1785-1920 CE): Jewelry became more elaborate and symbolic, with emphasis on large sets worn by women during important events like weddings and religious ceremonies. The iconic blue enamelwork, inspired by the city's architecture, became a hallmark of Bukhara jewelry. • 20th Century: Russian colonization and the Soviet era introduced new techniques

and materials, resulting in a blend of traditional and modern styles. The 19th century in Bukhara was marked by the flourishing of artistic crafts embossing and jewelry production, weaving, embroidery and gold embroidery, carving and painting on wood and ganch... Bukhara became the largest school of crafts, exerting a significant influence on the creativity of masters of other cities and villages. The art of the cities of the Muslim East, which included the capital of the Bukhara Emirate, was united over the centuries by a single style developed by Islamic ideas about beauty, 1

gravitating towards the utmost aestheticization of form, sophistication of lines, which was also typical for jewelry. Their style was distinguished by its fragmented form, abundance of pendants, loose joints, giving the product airiness, lightness, the use of filigree, openwork slots and grains, semi-precious stones - amethysts, beryls, tourmalines, corals. Special attention was paid to the production of jewelry in Bukhara, this reflected the society’s craving for luxury and wealth; In the central market of the city, jewelers were given a special place - Toki Zargaron1 - the dome of jewelers. It is known that in the 19th century. there were up to 400 jewelers in the city (1, p. 194). This craft was practiced by Uzbeks and Tajiks, Indians and Persians. The Indians, for example, owned small workshops for polishing and cutting precious stones (1, p. 176). Thanks to Caucasian jewelers, the mob became popular (2, p. 237). In general, the jewelry art of Bukhara was, as D. Fakhretdinova noted, “a complex syncretic phenomenon, in which much that was introduced by other peoples merged on the Tajik-Uzbek basis and ancient traditions” (3, p. 72). At the same time, one cannot help but notice that the borrowed forms were significantly modified under the influence of local fashion; In the multi-ethnic city that was Bukhara, a single set of decorations was formed, reflecting the characteristic features of urban fashion, regardless of its ethnic characteristics. Traditional Bukhara jewelry includes head decorations tilla-kosh (bride's crown), temple pendants mojitillo (bibishak) and kajak, chest jewelry zebi-gardan and nosigardan, earrings such as barg, kundalsoz, halka, etc., bracelets, decorated slotted openwork carving in the Islimi style, belts for the nobility with large silver buckles, etc. Many of these types of jewelry were made in other cities, for example, zebi-gardan and tillya-kosh. Zebi-gardan breast decorations are complex complexes consisting of a central large medallion-pendant and additional small rectangular medallions connected to each other by openwork chains running in several rows. They were decorated with enamel, semi-precious stones or colored glass, filigree, and numerous pendants. Similar decorations are known in Tashkent, Samarkand and other large cities. Tillya-kosh head decorations, the shape of which is probably associated with Indian tradition, were popular among both the Uzbek and Tajik populations, they were also similar to Samarkand, Tashkent and Kokand decorations. Of particular interest to researchers of jewelry art has always been the problem of the semantics of forms, the specificity of which lies in the fact that even forms that were made late in time are often associated with archaic, cult, predominantly astral ideas of the sedentary agricultural environment, or totemic ideas of the steppe people, so ancient that their meaning long forgotten. Analysis of the form and search for analogies make it possible to restore their genesis. For example, “sanchok” - a fragment of a Bukhara head pin (a crescent moon at the bottom, a star at the top; in Khorezm its version is known as “bodom-oh”, a frontaltemporal decoration) - is associated with astral symbolism (motifs of the sun (star) and moon), formerly popular both in the art of settled agricultural and nomadic populations. The symbols of the sun and crescent are popular among many eastern peoples and are 1

Toki Zargaron (Uzbek and Tajik Toqi Zargaron) is a traditional indoor bazaar in the historical center of Bukhara, Uzbekistan.

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associated with one of the most ancient astrocults - the worship of the Sun and Moon. The Moon was associated with the feminine, and the Sun with the masculine (4, p. 35). The sun is the supreme deity, the great fertilizing force; the idea of life in general has been associated with its image at all times. The crescent, in turn, symbolized the beginning of a new life cycle. The image of the crescent moon seemed to ensure the successful further development of life, and the sun - the protection of life itself. Two symbols nearby emphasized the cyclicality and continuity of the life process and probably reflected the idea of the equinox associated with the beginning of the new year according to the eastern calendar - the Navruz holiday. In general, the symbolism of jewelry of this kind is associated with the idea of fertility and involvement in the life-giving forces of nature. Astral themes were very common in Bukhara, where, before the adoption of Islam, Zoroastrianism and the worship of heavenly bodies, in particular the Moon - Mokh, were popular; At one time, the first city mosque, Magoki Attari, was erected on the site of the Moon Temple. Another evidence of the persistence of the astral cult is the name of the suburban village. Present Day: • Bukhara jewelry continues to be crafted using traditional methods, with a renewed appreciation for its heritage. • Contemporary designers are reinterpreting traditional motifs and techniques to create modern pieces that resonate with a global audience. Key Characteristics of Bukhara Jewelry: • Intricate craftsmanship: The use of granulation, filigree, and cloisonné enameling techniques. • Bold colors: Prominent use of turquoise, lapis lazuli, carnelian, and the iconic blue

enamel. • Symbolic motifs: Floral patterns, geometric designs, and Islamic calligraphy. • Large and elaborate sets: Jewelry designed for significant occasions like weddings

and religious ceremonies. • Multifunctional pieces: Jewelry often served as adornment, amulets, and

containers for religious texts. • Techniques of Bukhara Jewelry Art Bukhara jewelry art boasts an array of stunning and intricate techniques, each contributing to its unique beauty and cultural significance. Here are some of the most prominent techniques:

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Granulation: Granulation Jewelry This technique involves fusing tiny spheres of metal onto a base plate, creating a textured and shimmering surface. Jewelers use a blowtorch and a special tool called a "granulation tool" to place and melt the tiny metal balls onto the base. This technique is often used to create floral patterns and borders on jewelry.

Filigree:

Filigree Jewelry Filigree involves creating delicate designs and patterns using thin threads of metal. The threads are cut, shaped, and soldered together to form intricate motifs. Jewelers often use filigree to create delicate leaves, flowers, and other decorative elements on jewelry.

Cloisonné Enameling2: Cloisonné Enameling Jewelry This technique involves creating compartments on a metal base using thin strips of metal wire. These compartments are then filled with enamel powder and fired in a kiln. The enamel melts and fuses to the metal, creating a smooth and colorful surface. Cloisonné enameling is often used to create vibrant and intricate designs on jewelry.

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Cloisonné is a type of enamel decorative art done on a metal surface.

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Openwork Carving

Openwork Carving Jewelry This technique involves carving intricate designs into a piece of metal, creating a delicate and airy effect. Jewelers use a variety of tools, such as chisels and saws, to create openwork designs on earrings, pendants, and other jewelry pieces.

Turquoise Encrusting3:

Turquoise Encrusting Jewelry Turquoise is a revered gemstone in Central Asia, and it features prominently in Bukhara jewelry. Jewelers use small pieces of turquoise to create intricate mosaic patterns on jewelry, often incorporating them into cloisonné enameling designs.

Preparing a Bukhara Bracelet: A Step-by-Step Guide The process of preparing a Bukhara bracelet can be intricate and requires patience and attention to detail. Here's a step-by-step guide: Materials: • Metal sheet: Gold, silver, or copper depending on your preference. • Wire: Fine metal wire for filigree and cloisonné enameling (optional). • Granules: Tiny spheres of gold or silver for granulation (optional).

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Turquoise inlay is a technique of decorating metal surfaces with pieces of turquoise. It is inlaid with silver, bronze, copper. This technique is used to make dishes and decorations.

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• Turquoise: Small pieces of turquoise for encrusting (optional). • Enamels: Powdered enamels in desired colors (optional). • Tools: Hammer, anvil, saws, files, pliers, punches, blowtorch, soldering iron, enamel kiln

(optional), polishing cloths. Step 1: Design and layout: • Sketch your desired design on paper, incorporating traditional Bukhara motifs if desired. • Mark the layout on the metal sheet using a pencil or scribe. Step 2: Shaping the bracelet: • Cut the metal sheet according to your desired bracelet size and shape. • Use a hammer and anvil to shape the bracelet, creating a rounded or curved form. • Smooth any rough edges with files. Step 3: Filigree (optional): • Draw and cut fine metal wires according to your design. • Shape the wires into desired patterns (leaves, flowers, geometric shapes). • Solder the filigree elements onto the metal base using a soldering iron and solder. Step 4: Granulation (optional): • Create tiny spheres of gold or silver using a blowtorch and special tools. • Attach the granules onto the metal base using a blowtorch and tweezers. • Arrange the granules in desired patterns or textures. Step 5: Cloisonné enameling (optional): • Create compartments on the metal base using thin strips of metal wire according to your design. • Fill the compartments with enamel powder of your chosen colors. • Fire the enamel in a kiln at the appropriate temperature to melt and fuse the powder. • Polish the enamel surface for a smooth finish. Step 6: Turquoise encrusting (optional): • Cut small pieces of turquoise into desired shapes. • Inlay the turquoise pieces into the metal base using a bezel setting or other techniques. • Securely fasten the turquoise pieces in place. 6

Step 7: Finishing touches: • Polish the entire bracelet using polishing cloths to achieve a lustrous shine. • Check for any loose elements and ensure everything is securely attached. • Attach a clasp or closure mechanism to complete the bracelet. Tips: • Work in a clean and well-lit workspace. • Use proper safety gear like gloves and eye protection. • Start with simple designs and techniques as a beginner. • Practice patience and precision for achieving a high-quality finished product. • Consider taking classes or workshops to learn Bukhara jewelry making techniques.

Additional Techniques: • Embossing4: Creating raised designs on a metal sheet using hammers and punches. • Chasing: Creating designs on a metal sheet using a hammer and a chasing tool. • Stamping: Impressing designs on a metal sheet using a pre-made stamp. • Gemstone setting: Setting precious and semi-precious stones into jewelry using

various techniques like bezel setting and prong setting. These techniques, passed down through generations, continue to be practiced by skilled artisans in Bukhara today. Their dedication ensures the preservation of this ancient art form and its continued relevance in the modern world. Bukhara jewelry art is a unique blend of historical influences and contemporary adaptations. It continues to be a treasured art form, admired for its beauty and cultural significance.

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Embossing is a printing process for obtaining a relief image on the surface of a product.

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I. Jewelry craftsmanship - Harmony of Inner and Outer Beauty Jewelry art is not only a wonderful craft, but also one of the most ancient professions on earth. The history of jewelry craft dates back thousands of years, and during this time it has gone through many changes and transformations. Initially, jewelry performed not only a decorative function, but also served as amulets and had magical properties. Over time, jewelry has become an integral part of the culture of various peoples. It helped to create images of women of different social strata, and was also used to create costumes for celebrations, including dresses for brides. Each item created by the jeweler was valuable and unique because it was handmade. This gave it a special value and symbolized the lifestyle and culture of a certain people. Uzbek jewelry has an ancient history stretching back over three millennia. Such a long time has allowed the development of unique techniques and styles that make the jewelry of this country truly amazing. Not only beauty and grace, but also the magical properties of amulets and talismans make these products special. One of the most exciting archaeological discoveries was the discovery of a shelter in the settlement of Dalverzintepa 5 in southern Uzbekistan. Inside it, archaeologists discovered treasures belonging to the Kushan period. These precious items, weighing more than thirty-two kilograms, were made of gold and silver and decorated with precious stones. This indicates that the masters of Uzbekistan already then possessed high skill and a creative approach to creating jewelry. A feature of Uzbek jewelry is their unusual shape. Craftsmen use many small details and elements to create truly magnificent works of art. It requires a lot of patience, skill and attention to detail. Each product becomes unique and inimitable. Silver is the material of choice for many Uzbek jewelers. Unlike Bukhara craftsmen, who prefer to work with gold, Uzbek craftsmen create jewelry from noble metal, which has its own special charm. They skillfully combine silver with precious stones, creating amazing compositions and patterns. Each workshop in Uzbekistan has its own peculiarity and unique approach to the creation of jewelry. But what unites them all is a special horn with sheepskin furs. This forge is used to fan a charcoal fire, which is an integral part of the jewelry making process. This ancient craft is passed down from generation to generation, preserving the traditions and uniqueness of Uzbek jewelry art. Uzbek jewelry is a real work of art that reflects the rich culture and history of this country. They are not only beautiful and exquisite, but also have special symbolic meanings. To wear jewelry of Uzbekistan means to carry with you a piece of its unique heritage and spirit. One of the regions famous for its traditional jewelry and decorations for clothes is Central Asia, in particular Uzbekistan. Uzbekistan has long been famous for its rich heritage in the field of jewelry. Local craftsmen create amazing products, embodying the traditions and cultural characteristics of the people in them. One of the most famous types of Uzbek jewelry art is zardozi. This is a technique in which craftsmen create patterns and designs on metal using thin gold or silver wires. Zardozi adorns various items such as bracelets, necklaces, earrings and rings. Each product made in this technique is a real work of art. In addition to zardozi, Uzbek jewelers also use other techniques and materials to create unique jewelry. They use semi-precious stones, pearls, enamel, sirloin work and more. Each product has its own history and symbolizes the richness of Uzbek culture. 5

Dalverzintepa is an ancient settlement from the era of the Kushan Empire (1st–4th centuries AD), located in the Shurchinsky district of the Surkhandarya region, 60 km from Termez.

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The jewelry art of Uzbekistan is one of the most ancient and unique in the world. For thousands of years, craftsmen have passed on their skills and techniques for making beautiful jewelry from precious metals and stones from generation to generation. The history of this craft has more than twelve centuries, and each product created by Uzbek jewelers carries a rich cultural and historical value. One of the earliest finds of jewelry in Uzbekistan dates back to the 12th century BC. Jewelers in ancient times used both precious and semi-precious stones to create magnificent jewelry. Various materials were used in their work, such as pearls, turquoise, sapphires and garnets. However, it is interesting to note that these stones were predominantly cut rather than faceted before they were set into a piece of jewelry. In addition, the stones had special magical properties that gave them additional meaning. For example, turquoise was used to decorate the handles of weapons, as it was believed that this stone gives strength and courage to a warrior in battle. Beliefs in the magical power of stones were also widespread in other areas of life, where jewelry served not only for beauty, but also for acquiring certain properties and protection. The wedding was a special event where the girls were often presented with whole sets of jewelry. These sets became real treasures and were often passed down from generation to generation. It is interesting to note that many girls continued to wear these jewelries even after the wedding and before the birth of their first child. This was due to the tradition and symbolism that the jewelry carried. They became a kind of talisman and brought good luck and happiness to their owner. Thus, jewelry in ancient times not only served to decorate the body, but also had a deep symbolic meaning. They were associated with magic, beliefs and traditions, reflecting important aspects of the life and culture of that time. Each stone had its own unique power and meaning, making jewelry special and valuable. Today we can admire these works and learn about our past through their unique beauty and historical value. Bronze bracelets found at the source of the Chirchik River are amazingly beautiful and personify cosmological spirals. These jewelries testify that Uzbek jewelers already in ancient times possessed incredible skill and delicate taste. Another amazing treasure is the Amu Darya treasure found at the headwaters of the Amu Darya River. This treasure contains unique products of Bactrian jewelers who lived in the 5th century BC. Their work is distinguished by elegance and complexity of execution, and the use of a variety of stones and metals gives them a special appeal. However, perhaps the most sensational find is the treasure from the settlement of Dalverzintepe in the Surkhandarya region. A huge amount of jewelry made of gold and silver, inlaid with precious stones, was found here. The total weight of these jewelry was as much as 32 kilograms. This indicates that Uzbek jewelers hundreds of years ago already mastered complex manufacturing techniques and used valuable materials to create their works. Today, Uzbek jewelry art continues to flourish. Masters combine in their works the traditions of the past with modern trends. Their jewelry is distinguished by exquisite design, excellent handicraft and the use of quality materials. The history and traditions of Uzbek jewelry art are an important part of the country's cultural heritage. The unique decorations created by the masters of Uzbekistan not only delight with their beauty, but also tell us about the rich history and culture of this land. One of the priorities of the author's work is the revival of the ancient jewelry art of Uzbekistan. Mamur Fataev in his work relies on the centuries-old experience of his ancestors, bringing that original zest to the jewelry of Uzbekistan. 9

Golden Treasure of Bukhara: 19th Century Jewelry Art Jewelry art in the history of mankind has always been not only a way of expressing individuality, but also the embodiment of cultural values and historical experiences. In this context, one of the brilliant pearls of the world jewelry heritage was the city of Bukhara, which in the 19th century served as a center of craftsmanship, where amazing works of art were born that left their indescribable mark on the history of the jewelry era. The main center of jewelry art in Central Asia was the Taki-Zargaron ensemble, or the Dome of Jewelers, towering in the city of Bukhara. This architectural monument of the 16th century not only served as a place of trade and crafts, but also became a symbol of the importance of Bukhara jewelers and their skill. Under its arches there were workshops and shops, where craftsmen worked with incredible diligence, creating works that are now kept in museums and private collections. A feature of Bukhara jewelry of the 19th century is their conciseness and rounded shapes of softened corners. This gives the products monumentality and emphasizes the feeling of weight and significance. However, despite the presence of rounded shapes, attention to detail was maintained thanks to enlarged elements, contrasting colors and the technical savvy of the craftsmen. In the 19th century, Bukhara jewelers mastered a variety of techniques that made their products unique and inimitable. Casting, forging, granulating, openwork and applied filigree, engraving, niello, inlay with precious and semi-precious stones - all these techniques were used in the work of masters. A special place was occupied by the technique of gilding, which gave the products shine and luxury. An interesting fact is that in the 19th century, due to a negative attitude towards wearing gold items, Bukhara craftsmen resourcefully used the technique of gilding, creating jewelry from silver with gold plating. This has allowed them to retain their appeal and luster while remaining in line with cultural norms and restrictions. It should also be noted that the palace workshops of the Emir of Bukhara were the place where items made of pure gold were created. This indicates that the art of jewelry had a special place in the cultural life of the city and the country. The art of Bukhara jewelers of the 19th century left us an indescribable legacy that still delights us with its beauty, technical skill and deep meaning. These decorations not only serve as an example of high art, but also testify to the rich history and cultural heritage of Bukhara. Samarkand jewelry art of the 19th century is a unique combination of the Bukhara and Tashkent schools of jewelry art. It is distinguished by the use of various techniques, such as bosmas, filigree, casting, granulation, embossing, engraving, blackening, gilding 6 , as well as openwork filigree. One of the characteristic features of Samarkand jewelry is their lightness and weightlessness. Masters achieved this effect using the play of gaps and the masterful construction of monochrome compositions of products. The shape of the jewelry was created from small rings that looked like honeycombs and lined with flattened silver wire. Often, hanging silver chains were attached to such products, adding grace and elegance to them. In Samarkand at that time there were several famous master jewelers who left their mark on the history of jewelry art. I. Kamilbaev and H. Yuldashev were recognized experts in creating unique jewelry. Their works were distinguished by the highest quality of workmanship and original design solutions. Samarkand jewelry art of the 19th century continues to impress with its beauty and grace. These pieces of jewelry are not only luxury items, but also real works of art, which are still 6

Gilding is a decorative technique for applying a very thin coating of gold over solid surfaces such as metal (most common), wood, porcelain, or stone.

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admired for their sophistication and aesthetic impact. The history of Samarkand jewelry art is an important part of the cultural heritage of Uzbekistan. It testifies to the talent and skill of Uzbek jewelers who were able to create unique and inimitable works of art that reflect the richness and beauty of this land. The jewelry art of Uzbekistan in 1950-70 continued to flourish, especially in the cities of Tashkent, Bukhara, Samarkand, Kokand and Khiva. During this period, it combined traditional manufacturing techniques and retained the variety of forms of products characteristic of the previous time. However, new elements appeared in the jewelry art of Uzbekistan. For example, various types of earrings became popular in Bukhara, such as holak, wither-barg and shibirma, each of which had its own unique features and solutions. Bukhara earrings have become widely known and popular throughout the country. Shibirma is also a form of an earring, but with an openwork ornament in the form of a petal. She gave the products elegance and elegance. This style has become in demand among the jewelry of Uzbekistan. Important changes in the industry were organizational changes in the production of jewelry. In 1963, a jewelry factory was founded in Tashkent, which allowed the industry to go beyond handicraft production and move to a new level. It is also necessary to note the outstanding craftsmen who continued to engage in jewelry craft and preserved traditions. In Bukhara it was K. Mirakov, known for his Bukhara forms of earrings and necklaces "tapishi dil". A. Gafarov and M. Nazirkhonov worked in Tashkent, Sh. Ruzumurodov worked in Samarkand, A. Abdujaborov worked in Margilan, and M. Marupov worked in Urgut. Thus, the jewelry art of Uzbekistan in the 1950-70s combined traditional and new elements, while maintaining its uniqueness and attractiveness. It continued to delight people with beautiful and exquisite decorations, reflecting the wealth and culture of this land. It should be noted that modern masters of jewelry art of Uzbekistan actively cooperate with various associations and associations, such as the Union of Craftsmen of Uzbekistan Hunarmand, the Association of Folk Craftsmen Usto, Mussavir, Meros and others. This allows them to exchange experiences, ideas and preserve valuable knowledge passed down from their ancestors. One of the outstanding manifestations of the skill of Uzbek jewelers is silverware with corals and semi-precious stones. The creative imagination of such famous masters as F. Dadakhodzhaev, G. Tikaev, Sh. Nizamov allows them to create unique jewelry that is not inferior in beauty and thoroughness to the best examples of Uzbek traditional jewelry art. Their works attract the attention of visitors in art salons and become real works of art. However, interest in the jewelry art of Uzbekistan is not limited to classical forms and traditional jewelry. Artists from the Tashkent Jewelry Factory and the Zarafshan Jewelry Factory show interest in reviving ancient types of women's jewelry and creating modern designs based on ancient forms. As a result, unique gold rings, earrings and necklaces appear in the jewelry stores of the republic, which combine the beauty of the past and modern trends. The jewelry art of Uzbekistan is an integral part of the cultural heritage of the country. Using cutting-edge technology and modern trends, craftsmen skillfully combine historical heritage and modern design, creating unique and attractive jewelry. This allows us to preserve ancient traditions and attract the attention of both local residents and foreign visitors who appreciate the uniqueness and beauty of Uzbek jewelry art. Thus, the jewelry art of Uzbekistan continues to delight us with its beauty and sophistication. Thanks to the talent and skill of Uzbek jewelers, the ancient traditions of this 11

wonderful artistic craft are preserved and developed, embodied in unique and beautiful jewelry that personifies the richness of the culture of Uzbekistan. The jewelry art of Uzbekistan continues to develop at the present time. Masters keep the traditions of the past, but also experiment with new ideas and materials. This allows them to create jewelry that combines classic elegance with contemporary style. Thus, the Uzbek jewelry art is an important part of the cultural heritage and continues to amaze with its beauty and uniqueness. Each product created by Uzbek craftsmen is not only an ornament, but also a historical evidence of the rich culture and traditions of this land. Always the desire for beauty, whether it be the inner harmony of the soul or the outer sophistication of the appearance, has occupied an important place in human individuality. The desire for this harmony is the way to the expressiveness and attractiveness of the personality. In this unique article, we explore how jewelry, bearing a thousand years of history, plays an important role in creating a spectacular look and embodying art. Making real jewelry is an art that requires not only deep knowledge of materials and technologies, but also originality, taste, as well as a sense of proportion and tact. These last qualities play a special role, since jewelry is usually not only of impressive value, but also designed to express the subtlety of taste and elegance. Many of us know that the words "wealth" and "beauty" do not always merge into a single concept. Massive gold chains or stones lined up on the fingers can hide the true value of the jeweler's exquisite art. It is important not only to demonstrate your wealth, but also to learn to appreciate true beauty. The history of jewelry craftsmanship is rich in magnificent works of art. Jewelers and handicraftsmen from the 4th to the 20th century created masterpieces that carried sophistication and grace. Those who adequately showed their art, received the right to stamp gold and silver items. These hallmarks not only indicated the sample of the metal, but also stored information about the place and date of manufacture, as well as the name of the master. This hands-on approach to identifying the creator of the jewelery helped to preserve the uniqueness and individuality of each piece. History has left its mark not only on art, but also on the distribution of workshops around the world. Great cities such as Paris, London, Rome and Brussels admired the work of Russian and foreign jewelers, which displayed fine taste and craftsmanship. An important aspect of the art of jewelry is the choice of materials. The metals and stones used in the creation of jewelry embody the jewels and beauty of nature. Craftsmen carefully select materials to reflect their inspiration and convey unique stories. The art of jewelry making is not just about creating jewelry, it is about the ability to convey emotions and stories through precious stones and metals. It reminds us of the importance of harmony between the inner and outer world, and that true beauty lies in the details and subtleties. Mamur Fataev is constantly trying to involve people and show the real living beauty of the game of stones and metals. That is why he periodically exhibits his works at various forums and expositions, not only in the country, but also abroad. Jewel crafting: From Primitive Jewelry to Modern Masterpieces The eternal desire of man to decorate himself and his world stretched through the ages and evolution. The history of the development of jewelry is impressive with its variety of materials, techniques and styles, and it begins from ancient times. The Stone Age was the birth of unique jewelry made from stone, wood, bone, clay and shells. However, even at that time, people already felt the magical attraction of semi-precious stones such as rock crystal, carnelian, sapphires and rubies. The journey of man to metals began millennia ago, leading to the discovery of new 12

horizons in the art of jewelry. Many metals such as gold, copper, tin, and lead have been found in nature as significant nuggets. One impressive example is the discovery of over 400 tons of copper in North America. Especially valuable were gold nuggets, which became the basis for creating masterpieces of jewelry art. Gold and copper, in addition to their strength, also have excellent coloration, which makes them ideal materials for creating jewelry. In ancient civilizations, copper was the main material for creating jewelry, and bronze, an alloy of copper and tin, gave them even more strength and elegance. This is confirmed by the finds of many jewelries found in archaeological excavations. The first rings, bracelets and pendants were made by hand, had rough shapes, retaining the imprints of primitiveness. With the development of technology and art, the methods of making jewelry have also changed. Manual work gradually gave way to new methods. One of the significant moments was casting, which made it possible to create products of more complex shapes with greater detail. An example was the copper ax - the oldest known casting, which is already six thousand years old. Over time, jewelry art has gained worldwide fame, becoming an important part of the cultural heritage of various peoples. Modern jewelers not only continue to use traditional materials, but also introduce innovative technologies, embodying amazing ideas in metal and stones. The art of jewelry has evolved, combining tradition and modernity, and remains an eternal testimony to human creativity.

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II. Pure metals, non-precious alloys In the production of jewelry, the physical properties of metals and alloys, such as density, melting point, thermal expansion, thermal conductivity and reflectivity, are in the first place. Knowledge of these properties is necessary in order to correctly diagnose possible defects and defects that occur during procurement operations and affect the consumer properties of the products being created. Lack of such knowledge can lead to poor-quality manufacturing and fragility of jewelry products. For example, an improperly selected alloy can cause the product to warp or change when subjected to extreme temperature conditions. Therefore, in order to successfully create high-quality and durable jewelry, manufacturers must begin to carefully select and study the properties of metals and alloys, as well as follow the appropriate technological processes. In the various manufacturing methods used to manufacture metal parts for jewelry, gemstone settings, and cutlery, the basic mechanical properties of these products are important. Strength, hardness, elasticity and ductility are integral characteristics that affect their durability. Therefore, the selection of alloys for the production of jewelry should be based on an analysis of mechanical properties and taking into account operational requirements. However, in addition to mechanical properties, the chemical properties of metals and their alloys play an equally important role in the process of consuming jewelry. Metals such as rings, bracelets and chains have unique properties, including their resistance to various substances and environments. They can withstand the aggressive effects of acids, alkalis, gases, fresh and sea water. In addition, metals have a variety of physical, chemical, mechanical and technological properties. To determine these properties, the physical and technological characteristics of the metal or alloy are diagnosed using visual methods, for example, by examining them with the naked eye at a certain distance from the light source. In addition, one of the important properties of a metal is its color, which is determined by the spectral composition of the reflected or emitted radiation. Molten filler material, also known as solder, has the property of soldering metals, creating permanent joints. This is due to the ability of the metal to dissolve in acids. The plasticity of the metal allows it to undergo irreversible deformation, which is an important property in soldering. In addition, metals have other characteristics such as luster, magnetic properties, and corrosion resistance. Luster is the ability of a surface to reflect light, which gives metals an aesthetic appeal. The magnetic properties of metals are manifested in their ability to be magnetized or react to the action of a magnet. Corrosion resistance, in turn, is the property of metals not to collapse under the influence of aggressive media. All these characteristics influence the use of metals in various industries and everyday life. Non-ferrous and ferrous metals are the two main groups of metallic materials that are used in industry. Ferrous metals, such as iron and its alloys, differ from non-ferrous metals in their ability to be magnetized. Iron, the main representative of ferrous metals, has a silvery-white color and is distinguished by its brilliance, malleability and ductility. However, it rusts when exposed to air. Depending on the carbon content, iron alloys can be steel or cast iron. Unlike ferrous metals, non-ferrous metals are grouped according to similar properties. They can be light or heavy, refractory or fusible. One example of a non-ferrous metal is copper. This metal has a reddish-pink color and is soft and ductile. In addition, copper has high thermal and electrical conductivity. The use of ferrous and non-ferrous metals has a wide range of applications in various industries. Ferrous metals, for example, are used to create building structures, automotive parts, and industrial machinery. Non-ferrous metals, in turn, are used in the production of electronics, 14

electrical wires and pipelines. Both types of metals make a significant contribution to the development of modern industry and the economy as a whole. Copper, which has a Mohs-3 hardness, is an easily solderable material. In a humid environment, it becomes covered with a greenish coating of cuprous oxide. Interestingly, copper easily dissolves in nitric and concentrated hydrochloric acids. Brass, which is a copper alloy whose main alloying element is zinc, is yellow in color and easily deformed. It is also soluble in most acids. Bronze, in turn, is divided into tin, aluminum and beryllium compounds. Its color is golden yellow and it is both air and water resistant. However, it is easily soluble in nitric acid. Cupronickel 7 , a copper-nickel alloy, is an interesting material that has its own unique properties. One interesting copper-based alloy is nickel silver, which is composed of copper, nickel, and zinc. Outwardly, nickel silver is very similar to silver, its color is silvery white, but on the cut and polished parts you can see a yellowish tint. This alloy has softness and ductility, which makes it suitable for various machining processes. In addition, nickel silver is very resistant to corrosion in air, which makes it an excellent material for making jewelry. However, when interacting with a humid environment, the alloy may become covered with a green coating due to oxidation. Interestingly, nickel silver dissolves in nitric acid, which distinguishes it from other alloys. It should also be remembered that hot sulfuric and hydrochloric acids are corrosive to it, so you need to be careful when working with this material. In addition, it is important to note that the color of nickel silver can vary depending on the nickel content. So, an alloy with a high nickel content may have a bluish tint, while a low nickel content gives it a greenish color. An important advantage of nickel silver is its strength and ability to solder well. This makes it a sought-after material in various industries, including electronics and jewelry. In conclusion, nickel silver is an interesting and versatile alloy that combines strength, ductility and aesthetic appeal. It has found widespread use in a variety of industries and remains a popular choice for many projects and products. Zinc, a white metal with a bluish tinge, is brittle under normal conditions, but becomes ductile when heated to 100-150 degrees. In a humid environment, it becomes covered with a green coating, and completely dissolves in nitric acid. Hot sulfuric and hydrochloric acids corrode zinc, turning it into a dense layer of oxide of a dull gray hue in air. When heated in air, zinc in turn turns into a white powder. Zinc, in addition, is quickly destroyed under the influence of concentrated and dilute acids, as well as alkalis. However, zinc is not the only metal with similar properties. Cadmium, for example, is also a white metal that can develop a green coating when reacting with a humid environment. Cadmium is also soft, making it more malleable for a variety of processes and applications. It is important to note that both metals have reactivity and the ability to form compounds with various substances. These properties make zinc and cadmium important elements in industry

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Cupronickel or copper-nickel is an alloy of copper with nickel, usually along with small quantities of other elements added for strength, such as iron and manganese.

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and research. However, due to their reactive nature, special attention must be paid to their handling in order to avoid possible hazards. So, zinc and cadmium, despite their similarity in some chemical properties, have different aspects and applications. Understanding these features allows us to more deeply study and use these metals in various fields of activity. Malleable and ductile, cadmium has a significantly greater chemical resistance than zinc. In the process of heating in air, cadmium turns into a brown powder, releasing brown vapors. Vapors and salts of cadmium have toxic properties. Cadmium is molecularly soluble in nitric acid, but much less soluble in hydrochloric and sulfuric acids. Diluted hydrochloric and sulfuric acids have almost no effect on it. Nickel, a white metal with a yellowish tint, is hard, durable, and ductile. It has high reflectivity and weak magnetic properties. In addition, nickel is one of the chemically resistant metals. It is important to note that both cadmium and nickel have their own characteristics and specific chemical properties. Cadmium, in addition to its high chemical resistance, is also known for its toxicity, which makes its use in some areas limited. At the same time, nickel, due to its magnetic ability and reflective properties, is widely used in industry and production. Thus, although cadmium and nickel are different metals, both of them are of interest because of their unique properties and possibilities of their use in various industries and science. Tin metal, characterized by its silvery white color and plasticity, has amazing properties. It does not oxidize in air and does not corrode in a humid environment. However, tin dissolves in nitric acid, and hot hydrochloric and sulfuric acids can corrode this metal. When burned, tin forms a white powder. Concentrated hydrochloric and nitric acids easily dissolve it, although dilute one’s act poorly. But the strongest reactions occur when tin interacts with chlorine and iodine. Lead, in turn, is a bluish-gray metal that has a strong luster when cut. It is very malleable and can be easily cut with a knife. This is especially interesting given that lead is a heavy metal. Under normal conditions, lead is a stable metal. However, in a humid environment, it quickly becomes covered with a dark gray oxide film, which can adversely affect its chemical properties. Despite this, lead is resistant to the action of sulfuric and hydrochloric acids. Moreover, it dissolves well in nitric, as well as in acetic and citric acids. On the other hand, aluminum is a light metal that has a silvery bluish color. It has malleability and ductility, which makes it a versatile material for various industrial and domestic purposes. However, under normal conditions, it is not soldered by either contact or flame soldering. This is due to the fact that in air aluminum is instantly covered with a thin and very resistant oxide film, which protects it from destruction. However, aluminum is destroyed in water. However, it is resistant to concentrated nitric and organic acids. Thus, lead and aluminum are two different metals with different properties and chemical reactions. Their resistance to the environment and various acids determines their use in various industries and scientific research. To carry out the diagnostics of metals and alloys, a specially equipped laboratory with exhaust devices is required, where samples can be quickly dissolved in hydrochloric concentrated sulfuric acid. Determination of the color and gloss of metals and alloys is carried out using daylight, as a result of which the samples must be polished for more distinct recognition.

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In addition, a set of pliers and hardness pencils must be used to determine processing properties such as hardness and ductility. If it is required to determine corrosion resistance, then it is recommended to use a standard set of acids and alkalis, which are usually used in chemical laboratories. Thus, successful diagnostics and determination of the properties of metals and alloys require not only specialized equipment, but also the right approach to the choice of reagents and experimental conditions. The results of laboratory studies allow us to draw a conclusion about the composition of the alloy. A new method for determining the composition of an alloy is based on the use of a touchstone and assay reagents, which allows more accurate determination of the composition of the alloy. The process consists of a streak test in which the alloy reacts as a non-precious nonferrous alloy. This is due to the solubility of alloying metals under the influence of nitric acid. Thus, the new method is a more reliable and accurate way to determine the composition of the alloy. The Art of Casting: From the Copper Age to Bronze Luxury Mankind has always sought to translate their creative ideas into a material form, and casting has become one of the important methods for achieving this goal. This ancient technology allows you to create products of a wide variety of shapes and sizes. In this article, we dive into the art of casting, exploring its evolution from the Copper Age to the Bronze Age and discovering the amazing properties of the alloys that have made the process so important and popular over the centuries. Copper and the Copper Age The first steps in the art of casting were made in ancient times, during the period that is now called the Copper Age. Copper, with its toughness and flexibility, made it possible to create amazingly detailed products. However, pure copper had its drawbacks - it is prone to deformation, oxidation and loss of its original luster. However, it was the first step in the world of casting, which led to the further development of technology. Copper jewelry is not only a stylish addition to the image, but also a source of many useful properties for the body. Due to its unique properties, copper can have both positive and negative effects on human health. The material from which copper jewelry is made contains salts that have a bactericidal effect. They are able to destroy a large number of fungi and bacteria in the body. This makes copper an effective tool for fighting various infections. But the beneficial properties of copper are not limited to bactericidal action. It also has a positive effect on metabolism and blood circulation. Because of this, antique copper jewelry has often been used in medicine to improve the general condition of patients. More recent research suggests that copper jewelry can also be beneficial for weight loss. The metal stimulates the lymphatic system, which helps to remove excess fluid from the body. In addition, copper helps to normalize the nervous system and improve sleep. It can also stabilize the emotional background. However, do not forget about the potential harm of copper jewelry. Some people may experience an allergic reaction to copper, so it's a good idea to check with your doctor before using jewelry. In addition, low-quality copper products may contain lead, which can adversely affect health. 17

Thus, copper jewelry can be beneficial to the body, but one should be careful and careful when choosing and using them. It is important to understand that everybody is different, and what works for one person may be harmful for another. Wearing copper accessories is a trendy and stylish way to express your personality. In addition to aesthetic pleasure, such products can also have health benefits. The human body has an amazing ability to independently control and regulate the amount of accumulated substances necessary for normal functioning. Therefore, there are no restrictions on the use of copper accessories. Wearing copper accessories can have a beneficial effect on the body. The copper contained in them has antibacterial properties, which helps maintain hygiene and prevent infections. In addition, copper has anti-inflammatory properties, which can be beneficial for people suffering from inflammatory conditions. However, despite all the positive aspects, it is worth remembering that wearing copper accessories is not a universal remedy for treatment or prevention. To achieve the maximum effect, you should consult a specialist or doctor who can choose the most appropriate method of treatment or recommend additional measures to maintain health. Bronze is one of the most common copper alloys, which is obtained by alloying copper with various elements, with the exception of zinc, which forms an alloy known as brass. Each grade of bronze is identified by the letter "Br" followed by the capital letters of the alloying elements and the percentage of copper, and then the percentage of each alloying element. Bronze alloys can have varying degrees of hardness, depending on their condition. They can be supplied in soft condition (after annealing and hardening), semi-hard condition (with reduction within 1030%), hard condition (with reduction within 30-50%) and extra hard condition (with reduction more than 60%). One of the varieties of bronze is tin bronze, in which the main alloying element is tin. Tin bronzes differ from tin or lead based alloys, which are called babbits and are marked with the letter "B" followed by a number indicating the tin content of the alloy. Bronze has a wide range of uses due to its unique properties. It has high strength, good corrosion resistance and excellent thermal and electrical conductivity. Bronze alloys also have good machinability, making them an ideal choice for a variety of applications including mechanical parts, electrical contacts, musical instruments, and more. Tin bronzes, due to their high resistance to wear and friction, are widely used in the manufacture of bearings and other parts operating under high loads. They also find use in marine equipment as they are resistant to salt water corrosion. In conclusion, bronze is an important material that has found application in many industries. Its unique properties make it indispensable for creating strong, durable and reliable products. Whether used in mechanical, electrical or other applications, bronze remains one of the most popular materials due to its versatility and reliability. Bronze: Transformation into Beauty The important discovery resistance time.

change of eras - the transition from the Copper Age to the Bronze Age - brought changes to the art of casting. Bronze, an alloy of copper and tin, has become a real for casting masters. This alloy possessed incomparable hardness, strength and to oxidation. It also lends itself well to polishing, retaining its brilliance for a long

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In ancient times, bronze was an integral part of various household items and art. Bells, furniture, utensils, as well as weapons and shells were made from this durable casting material. However, bronze was especially popular in the creation of statues, sculptures and decorative objects. Its unique properties made it possible to create amazing ashtrays, figurines, lamps and accessories. In addition, cast bronze was used to make machine parts, including those that worked underwater. Over time, bronze jewelry became less popular. However, in ancient times they were an integral part of the human appearance. Rings, bracelets, necklaces and brooches were made from this noble material. To give additional charm, bronze was decorated with stones and glass. Today, the use of bronze in jewelry is not as common as it used to be. However, like brass, it is suitable for wax casting. A distinctive feature of bronze is its color, which is perhaps the reason why brass has lost popularity. Despite this, bronze remains an affordable material that is widely used among jewelry lovers. Chemical composition. Bronze is not a homogeneous alloy. Over the centuries, the chemical composition of bronze has changed, giving it different properties and purposes. The earliest bronze items contained only 1-1.5% tin, while later specimens included up to 15-16% tin. This made it possible to create a variety of products with varying degrees of hardness and color. Tin is one of the important elements used in the production of various alloys, especially bronze alloys. However, the limiting solubility of tin in copper is only 15.8%. If the tin content exceeds this limit, then a eutectoid is formed in the alloy structure, consisting of the Gu3Sn8 phase with a complex cubic lattice. The eutectoid has a high hardness, but at the same time it 19

becomes brittle, which leads to a decrease in the toughness and ductility of the alloy. That is why bronzes with a tin content of up to 10% have practical applications. They have sufficient strength and ductility for use in various industries. Tin bronzes containing up to 6-8% tin have a single-phase structure in the equilibrium state. However, non-equilibrium crystallization may form a small amount of another phase known as the 3-phase. This can affect the casting properties of the alloy. To improve the casting properties of tin bronzes, additives of zinc, lead and phosphorus are often used. Replacing part of the tin with zinc and lead helps to increase the fluidity and reduce the shrinkage porosity of the alloy. In addition, such replacement can reduce the cost of the alloy, which is an additional advantage. Tin bronzes have a wide range of applications, especially in the manufacture of products requiring high strength and wear resistance. They are used in aviation, shipbuilding, electrical and other industries. Due to their unique properties, tin bronzes continue to be in demand materials in modern production. Bronze, such a strong and beautiful material, has many uses in various industries, including jewelry. In addition to well-known components such as zinc and lead, some bronzes also contain nickel. The addition of nickel to the alloy gives bronze new decorative properties and a beautiful silver hue. Nickel is a valuable metal that is widely used in various industries, including jewelry. Its use in bronze gives this alloy its unique characteristics. Nickel has a high corrosion resistance and the ability to retain its luster and color for a long time. These properties make nickel bronzes ideal for creating durable and aesthetically pleasing jewelry. Color Splendor Jewelry bronzes containing nickel are multi-component alloys in which there are various proportions of zinc, lead and nickel. This allows makers to create a variety of bronze tones that can range from pale silver to richer, warmer tones. This flexibility in color choice allows jewelers to create unique and personalized pieces that combine the strength of bronze with the elegance of silver. This natural spectrum of colors made bronze a valuable material for jewelry. Its deep and warm shade attracted the eye and gave the products a special sophistication. Bronze jewelry containing nickel is not only visually appealing, but also highly durable and long lasting. Nickel bronzes are environmentally resistant, corrosion-resistant and retain their luster and color even after prolonged wear. This means that nickel bronze jewelry will delight its owners for many years to come, retaining its original beauty and appeal. In addition to jewelry, nickel bronzes also find use in other areas such as the manufacture of musical instruments, architectural elements, and even in the manufacture of coins. Their unique properties make them indispensable in many industries that require a combination of strength, aesthetic appeal and durability. Thus, adding nickel to bronze is an important step in creating unique and beautiful jewelry. Nickel bronzes have not only excellent decorative properties, but also strength, corrosion resistance and durability. These characteristics make nickel bronzes an ideal choice for those who value quality and elegance in jewelry. Due to its unique properties, bronze has found wide application in art and production. Bronze products can be found in archaeological finds all over the world - in Europe, Africa, Asia and America. Alloys with different percentages of tin were used for different purposes: bronze with a high tin content (13-16%) was used to create wear-resistant weapons items.

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Nickel silver Nickel silver products are not only elegant jewelry, but also real works of art. Nickel silver is an alloy created using copper, nickel and zinc. This tri-component alloy has unique properties that make it a valuable material for jewelry making. The color of nickel silver is reminiscent of silver and gives products made from this alloy a sophisticated and stylish look. But the attractiveness of nickel silver is not limited to its appearance. This material has exceptional plasticity, ductility and strength, which allows you to create jewelry with a variety of shapes and patterns. In addition, nickel silver has a high corrosion resistance, making it an ideal choice for everyday wear. Products made of nickel silver will not fade over time and will delight with their brilliance for many years. It is important to note that nickel silver does not cause allergic reactions, which makes it safe to use. Thus, nickel silver products are not only beautiful and elegant jewelry, but also strong and durable accessories that will emphasize your style and personality. Nickel silver's unique properties make it an ideal material for creating jewelry that will delight its wearer for years to come. In recent years, nickel silver has become an increasingly popular material in the jewelry and art fields. Its unique properties and aesthetic appeal make it ideal for fine jewelry and cutlery. But one of the main advantages of nickel silver is its ability to be used in creating filigree patterns. 21

Filigree is a true art that requires skill and patience. Jewelers create the finest patterns from wire or ribbon, which are then soldered to the base. Nickel silver, due to its ductility and strength, is an ideal material for this process. It allows you to create complex and exquisite details, giving the products a unique and elegant look. Not only jewelers, but also artists use nickel silver in their work. It is an excellent material for creating sculptures, reliefs and other artistic works. Its ability to easily obey shapes and retain details makes it an indispensable tool for artists, allowing them to express their creative idea in the subtlest details. Thus, nickel silver is not only just a metal, but also a real source of inspiration for creative people. Its unique properties and possibilities are revealed in the hands of masters who create unique and exquisite works of art. Thanks to nickel silver, the world becomes richer and more beautiful, filled with unique and aesthetically pleasing products. The unique properties and attractive appearance of nickel silver make it one of the most popular materials in the jewelry industry. This alloy gives us the opportunity to enjoy beautiful and durable jewelry that will delight us for many years. In addition, nickel silver has a high degree of corrosion resistance, making it an ideal material for creating jewelry that will look new and fresh even after long periods of use. Its strength and resistance to damage are also advantages of nickel silver, since jewelry made of this material is not easily damaged or distorted. Whether it's a ring, chain or bracelet, nickel silver jewelry deserves to be worn and admired. Not surprisingly, this material remains a popular choice for those looking for elegant and durable jewelry. Brass: Imitation Gold. Eternal Art Casting Since its inception, metals have always attracted the attention of mankind. Originally used as tools and ornaments, they have evolved to become part of culture and art. One such wonderful material that carries the brilliance and grandeur of gold is brass. Brass is an alloy formed by combining copper and zinc. This metal has a golden hue that brings it closer to a noble metal, making brass an ideal choice for imitating gold. The art of creating brass has long been a closely guarded secret of casting masters. The specialists not only strived to achieve the perfect golden hue, but also maintained a balance between copper and zinc in order to achieve optimal properties and strength of the alloy. With the passage of time and the development of technology, the art of casting remains relevant. Modern craftsmen and designers can create complex and unique items from brass and other alloys, continuing the traditions of the old masters. This allows us to preserve the spirit of ancient techniques and translate them into modern works of art. The composition of brass varies depending on the desired characteristics of the alloy. Copper ranges from 55% to 95%, and zinc ranges from 5% to 45%. Additional elements such as tin, nickel and manganese may be added to improve the casting properties of the metal. Plain brasses are marked with the letter "L" and the percentage of copper, which makes it easier to determine the composition of the alloy. The properties of brass also make it an attractive material for jewelry and decor. This metal lends itself well to polishing, welding and rolling. It is resistant to high temperatures and corrosion, making it a durable and reliable choice. Brass is also able to resist weathering, allowing it to retain its luster even after many years.

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But even “eternal metal” 8 requires care. To preserve its magnificent appearance, it is recommended to varnish the surface of brass, which will protect it from blackening. This is especially important for products that are in conditions of high humidity or exposure to aggressive environments. Thus, brass continues to be the epitome of luxury and sophistication. It not only imitates the brilliance of gold, but also embodies the timeless art of casting. Modern masters, inspired by the traditions of the past, continue to create works that will delight the eyes and delight the hearts of many generations. Brass is an amazing material that has found application in many areas of our lives. Although often associated with counterfeiting gold, brass products have their own unique properties and benefits. In everyday life, we rarely come across brass, but we certainly know about brass samovars. They are famous for their ability to warm up evenly, not burn through and retain heat for a long time. In addition to samovars, brass is widely used in the creation of accessories, machine parts, ships and appliances, coils and springs. However, that's not all. Brass is also a popular material for the production of orders, medals, church utensils and wind instruments. In jewelry, brass occupies a special place. Already in the 18th and 19th centuries, brass jewelry was sold under the guise of gold, which is why it was called "fake gold". Today, brass is used to create jewelry and inexpensive jewelry. Beginning jewelers often practice on brass brands L62 and L68, as their properties are similar to 583 gold. Rings, earrings, pendants, bracelets, as well as vintage and ethnic jewelry are made from brass. Brass has plasticity and ease of processing, so it can be blackened, silvered and gilded.

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Brass got its name “eternal metal” for its wear resistance.

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Modern demand for brass is growing, and this is due to people's interest in handmade jewelry, such as wire wrap. Brass is also excellent for wax casting, and its golden color makes it more popular than bronze. Thus, brass is a versatile material that has found application in various industries. Its unique properties and aesthetic appeal make brass products popular with people looking to stand out and add a touch of flair to their daily lives. Melchior The copper-nickel alloy Melchior, with a nickel content ranging from 18 to 20 percent, has incredible properties. Its melting point is 1170°C and its color is silver, making it an ideal material for various products. The flexibility and ductility of Melchior make it easy to work with, cutting tools easily penetrate this alloy, and it also lends itself well to soldering. After processing and polishing, it retains a shiny surface for a long time. One of the advantages of Melchior is its ability to imitate silver. Due to this, it is widely used in the production of tableware and inexpensive jewelry, decorated with semi-precious and semi-precious stones. This alloy is distinguished not only by its attractive appearance, but also by its affordable price, which makes it popular among consumers. Products made from Melchior are an excellent option for those who want to acquire stylish and elegant jewelry without overpaying for natural silver. Due to its unique properties, this alloy continues to win the hearts of people, becoming an indispensable material for the production of various products. The Perfection of Bronze and Silver: The Pursuit of Eternity and the Tradition of Jewelry in Uzbekistan For five millennia, bronze has been the epitome of beauty and strength, becoming the material of choice for fine art. From statues and bas-reliefs to ornaments and chandeliers, bronze serves as an inspiration for the masters of art, and in Uzbekistan this ancient metallurgical tradition interacts with the national culture, creating a unique heritage. The secret of the success of bronze works is not only the high fluidity and low shrinkage of this metal, but also its ability to support various types of processing. The perfection of bronze details is achieved through careful forging, chasing, cutting and engraving. However, over time, the magnificent color of bronze changes under the influence of the environment, acquiring a patina of different shades. Patina, closely associated with oxides and carbonic salts of metals in the composition of bronze, personifies the art of the time. From delicate light blues and greens to deep browns and blacks, patina becomes an indispensable companion to bronze pieces. Even in industrial cities, where the influence of sulfur gives the patina a black tint, this natural evolution of the metal emphasizes its uniqueness. In the context of the cultural heritage of Uzbekistan, jewelry art plays a special role. An integral feature of local craftsmen is the preference for silver. This noble metal, in addition to its unsurpassed aesthetics, has the ability to protect jewelry from negative factors. Silver earrings, bracelets and pendants are a testament to craftsmanship and indescribable individuality. Making even one piece of jewelry can require a whole day of the master's efforts. Complex orders may take up to 2 months. This process requires perseverance, patience and accuracy. Masters value their profession and are ready to share their knowledge and skills with the younger generation, preserving the spirit of arts and crafts. The Bukhara jewelry heritage is a symbiosis of times and cultures, where bronze and silver represent eternity and individuality. The 24

works of these masters captivate with their exquisite beauty and power, conveying to us the history of art, interaction with the environment and the endless pursuit of perfection.

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III. Treasures of Uzbekistan: 19th Century Jewelry Art The art of jewelry craft is an integral part of the cultural heritage of every nation. In the 19th century, Uzbek jewelers elevated this art to the highest perfection, using a variety of techniques and unique materials to create indescribable masterpieces that still amaze with their beauty and magical significance. While the world was changing around them, the Uzbek masters of jewelry art firmly held the traditions, passing their experience from generation to generation. Silver was the main material for creating jewelry. In folk beliefs, this metal was endowed with special sacred properties, it was considered "pure" and protected from evil influences. Gold, as a more expensive metal, was used with caution - its coatings decorated only individual details, adding brilliance and luxury to products. The magnificent decorations of Uzbek masters surprised not only with their materials, but also with their skill in processing precious and semi-precious stones. Lal (ruby), garnet, beryl, mother-of-pearl, pearls, carnelian, turquoise and corals - all these stones not only served as decoration, but were also symbols of various wishes. From health and love to prosperity and childbearing, each stone carried a unique energy and magical meaning. Masters with exceptional care selected stones for each product, creating unique compositions that helped strengthen spiritual and emotional ties. The uniqueness of the Uzbek jewelry manufactory was also expressed in the use of various metal processing techniques. From casting to engraving, from embossing to openwork filigree each technique gave the products originality and sophistication. The combination of different techniques created amazing textural effects that gave the jewelery depth and movement. Jewelry from the 19th century embodies the spirit and beauty of that time. They are not only magnificent decorations, but also a source of unique cultural heritage. In the collection of the Russian Ethnographic Museum in St. Petersburg, you can find some of the most striking examples of this art, representing the traditional jewelry heritage of Bukhara, Samarkand, Tashkent and other cities of Uzbekistan. In the 19th century, Uzbek jewelers created not just jewelry, but real works of art that carry a deep meaning and magical energy. Their craftsmanship, passed down through the centuries, continues to inspire and delight with its beauty and sophistication, leaving an indelible mark on the history of art and culture. Also, all this art flourishes and is being revived thanks to such masters as Mamur Fataev. The jeweler is strictly true to his ideology, he does everything to return the foundations of ancestors to the culture of jewelry making Silver This metal is one of the most brilliant and beautiful metals, which attracts attention with its brightness and unique properties. White or grayish white in color, it has not only aesthetic appeal, but also a number of other amazing characteristics. One of the most important properties of silver is its malleability and malleability. This metal can be easily drawn into thin wire or forged into thin sheets that are even thinner than paper. Thanks to these properties, silver has found wide application in the creation of jewelry, dishes and other items. One of the most amazing properties of silver is its reflectivity 9 . It 9

Reflectivity is the ability of a surface to reflect light. Silver is renowned for its high reflectivity in the visible region of the spectrum, making it an ideal material for mirrors, optical instruments and other applications that require efficient reflection of light.

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outperforms other metals in this regard, making it ideal for use in mirrors and other reflective surfaces. Due to this property, silver is also widely used in photography and optics. Silver also has antimicrobial properties. When silver objects are immersed in water, an oxide film forms, which releases silver ions. These ions have antibacterial properties and can destroy bacteria and other microorganisms. That is why during the campaigns of Alexander the Great, his soldiers using silver utensils were less likely to suffer from infections. This discovery led to the fact that the great commander ordered to supply the entire Greek army with silver vessels. But apart from these unique properties, silver also has other characteristics. For example, its density is about 10.5 g/cm³ and its melting point reaches 960.5°C. These parameters make silver easy to process and ideal for use in various manufacturing processes. In conclusion, silver is not only a wonderful metal for jewelry and home decoration, but also a material with unique properties. Its brilliance, plasticity, reflectivity and antimicrobial properties make it indispensable in many areas. Whether used in jewelry, glassware, or scientific research, silver has always been one of the most valuable and amazing metals on earth. Fine silver, also known as sterling silver, is one of the most popular alloys used in jewelry making. It is composed of 92.5% pure silver and 7.5% copper, which gives it strength and shape stability. Stamped "925" on the product indicates the use of sterling silver. One of the main reasons why jewelers and designers prefer sterling silver is its ease of processing. Thanks to this, craftsmen can create complex and unique jewelry, embodying their creative ideas. In addition, sterling silver is affordable, which makes it attractive to a wide audience. One of the benefits of sterling silver is its high strength to weight ratio. This means jewelry made from this alloy is light and comfortable to wear, yet strong enough to withstand everyday use. They retain their shape and luster over time, making sterling silver a popular choice for everyday jewelry. It is important to note the difference between jewelry and technical silver. Technical silver, which is used in industry, has other characteristics and purposes. It does not have an external luster, since its main purpose is to provide certain functional characteristics. The composition of technical silver may contain impurities of copper, nickel, tin, aluminum and cadmium, but their percentage is usually small - no more than 0.1-0.2% of the total composition. Unlike jewelry silver, industrial silver focuses on electrical conductivity and chemical resistance. Thus, sterling silver is an ideal choice for creating beautiful and durable jewelry. Its ease of processing, affordable price and high strength-to-weight ratio make it popular with crafters and buyers. Don't forget to check the 925 stamp on the item to make sure it's made from sterling silver. Jewelry silver and technical alloys are two different categories of materials, each of which has its own characteristics and purpose. The main differences between them stem from the purposes for which they are created. Jewelry precious metals such as silver, gold and platinum are primarily used to create jewelry and have an aesthetic function. Therefore, they must be durable and hard wearing to withstand everyday use. Often, jewelry materials can contain high concentrations of impurities that give them a special shine and color. However, when making jewelry intended for regular use, the addition of harmful impurities is usually avoided in order to minimize the risk of allergic reactions or other undesirable effects in humans. In contrast, technical alloys such as bronze or stainless steel are designed for their functional properties rather than their aesthetic appeal. The main purpose of these alloys is to provide high electrical and thermal conductivity, as well as strength and wear resistance under certain conditions. To achieve these characteristics, 27

the composition of technical alloys may include various impurities that can be harmful to humans. For example, nickel, often used in stainless steel, can cause allergic reactions, and lead, which is used in some alloys, can cause headaches. Thus, the main differences between jewelry silver and technical alloys lie in their purpose and composition. Jewelry materials are designed for an aesthetic function and usually do not contain harmful impurities. In contrast, technical alloys are designed with functional properties in mind and may contain additives that may be harmful to humans. Therefore, when choosing between them, it is important to consider not only the appearance and style, but also the intended use and possible health risks. Jewelry silver is one of the most popular materials for making jewelry. It attracts attention with its brilliance, beautiful color and durability. Among the various types of silver jewelry, sterling silver holds a special place. Sterling silver, also known as 925 sterling silver, is the quality standard for jewelry in many countries, including the United States. This alloy consists of 92.5% silver and 7.5% other metals, usually copper. The addition of copper gives silver extra hardness and strength, making it ideal for creating precious jewelry. One of the benefits of sterling silver is its ability to retain its luster and beauty over time. Sterling silver does not tarnish or oxidize as quickly as pure silver. It also has durability, making it ideal for fine detail jewelry. However, keep in mind that sterling silver is softer than some other metals. This means that thin jewelry or jewelry with fine details can be deformed under strong tension. Therefore, when wearing sterling silver jewelry, it is recommended to be careful and avoid strong exposure to them. One of the benefits of sterling silver is its hypoallergenicity. For those who suffer from allergies to nickel or other metals found in many jewelry, sterling silver is an excellent choice. It does not cause allergic reactions and allows you to wear jewelry daily without risk to health. In conclusion, sterling silver is an excellent choice for jewelry lovers. Its beautiful color, luster, strength and hypoallergenic properties make it popular among consumers. Whether you are looking for subtle jewelry or jewelry for daily wear, sterling silver is a great option that combines quality and aesthetic appeal. Sterling Silver: Timeless Elegance and Affordability Sterling silver is not only a great material for creating jewelry, but also a real way to follow the latest fashion trends without breaking your budget. Its brilliance and brilliance make jewelry made from it eternally elegant and attractive for many years. One of the main advantages of sterling silver is its versatile color, which is easy to pair with other metals such as white gold. This allows you to create many elegant and sophisticated combinations, emphasizing your individual style. It is important to note that sterling silver is available for almost any occasion. From important events and special occasions to everyday use, it is suitable for any occasion. Whether you're attending a wedding, celebrating a birthday, or just hanging out with friends, sterling silver jewelry will help you look flawless, beautiful, and sparkly at all times. However, it is worth noting that silver can oxidize over time, which can affect its brilliance and brightness. To avoid this, many sterling silver jewelry goes through a rhodium process. Rhodium plating is the coating of silver with a layer of rhodium, which prevents oxidation and gives jewelry extra shine and brightness. This allows you to keep your silver jewelry in perfect condition for a long time. 28

Thus, sterling silver is an excellent choice for those who appreciate elegance, affordability and the ability to keep up with fashion trends. Its brilliance, versatility and rhodiumability make it the perfect material for creating jewelry that will delight you for years to come. Don't miss the opportunity to add some sparkle and style to your life with sterling silver. Rhodium-plated silver is a process in which silver jewelry is coated with a layer of rhodium, a rare and precious metal. Rhodium is even rarer and more expensive than gold. Rhodium plating is applied to 925 sterling silver, also known as standard 925 sterling silver. This allows you to maintain or restore the brilliance of jewelry. The main purpose of plating silver with rhodium is to prevent oxidation. Without rhodium plating, the surface of silver jewelry is susceptible to oxidation in contact with air and skin. You may have already noticed this process on your silver necklaces, bracelets or rings: they have faded and taken on a darker hue with spots. The rhodium plating not only protects the silver from oxidation, but also gives it a whiter and more radiant appearance. It also highlights the brilliance of the gemstones that your jewelry can be embellished with. Thus, rhodium-plated silver becomes a more valuable and precious material compared to ordinary 925 sterling silver. However, it is important to note that rhodium plating can wear off or wear off over time. Therefore, it is recommended to periodically re-plating with rhodium to maintain the brilliance and beauty of your silver jewelry. This can be done by contacting a jeweler who will carry out the birthing process again. In addition, it should be remembered that rhodium plating can only be applied to the surface of silver, and not to all of its components. Therefore, when wearing jewelry made of rhodium-plated silver, strong friction or the use of abrasive products should be avoided so as not to damage the coating. In conclusion, rhodium sterling silver is an excellent choice for those who want to combine the beauty of silver with durability and protection against oxidation. This coating makes silver jewelry shine, making it more precious and attractive. Don't forget to renew the rhodium plating to keep them beautiful for a long time. Matte Silver: A fusion of Gloss and Elegance. Jewelry art is a beautiful fusion of talent, passion and technical skill. In the world of jewelry, there are many methods and materials that allow craftsmen to bring their fantasies to life. One of the most exciting and trendy trends is the use of matte silver, which brings a new harmony of gloss and elegance to the world of jewelry. Matte Glow Mystery Matte sterling silver is the result of a bold and painstaking treatment of 925 sterling silver. The metal undergoes a special polishing process, creating a stunning matte effect that becomes a unique feature of each piece. This technique is used to add a special texture and depth to products. Matte silver is ideal for creating accents, highlighting certain parts of the jewelry and giving them a mysterious charm. The symphony of the author's design of jewelry works of art, created by the author's designers, is like the melodies of great composers - each piece is unique and sounds in its own unique harmony. Aesthetics, set by an inspired master or a creative team, prevail in designer jewelry. Often, precious and exotic materials, as well as handmade elements, are used in such works, which gives the jewelry a special value. Collections of designer jewelry can include dozens or even hundreds of design variations, motifs and techniques. The process of creating designer jewelry often starts with manual prototyping and can then be scaled up to be produced in large quantities. Sometimes even celebrities contribute by sketching and defining the overall aesthetic, resulting in jewelry that combines starry brilliance with designer sophistication. Bridge between art and technology. I wonder how it is possible to combine handmade and technological solutions? The answer lies in the technologies that make design ideas a reality. 29

Even those designer jewels that are produced in large quantities retain their uniqueness through the use of innovative production methods and high-precision technologies. As a result, matte silver and designer jewelry complement each other, creating a magical harmony of gloss and elegance. These unique trends not only add personality to jewelry, but also allow everyone to carry a little piece of art and passion within them, expressing their individuality and taste. Silver is a noble metal that has been used in jewelry and art for many centuries. Its attractive luster and unique properties make it a popular material for jewelry and home furnishings. However, like any metal, silver has its own characteristics, among which darkening is the most common drawback. Silver is highly resistant to water and atmospheric oxygen under normal conditions. However, due to the presence of hydrogen sulfide in the air, over time, a thin, dark coating of silver sulfide may form on the surface of the silver. This phenomenon may not be desirable, especially for jewelry, which should always look shiny and attractive. In addition, silver reacts with ozone to form silver oxide deposits. It can also darken silverware, especially when exposed to high ozone environments for a long time. Tarnishing silver can cause it to lose its natural luster and attractiveness. If we talk about alloys of silver with copper, then they are the most common in the jewelry industry. Copper, which is the main component of these alloys, can also form copper sulfide deposits. The higher the copper content in the alloy, the faster the product will be subject to darkening. However, silver alloys with a lower copper content are more resistant to tarnishing and retain their luster for a long time. Therefore, in order to create products that are resistant to tarnishing, it is recommended to use silver alloys with a fineness from 875 to 960. There are several ways to combat the tarnishing of silver. One of them is regular cleaning of products using special products designed for silver. You can also use special storage products that will help prevent oxidation of silver during storage. It is important to remember that proper care of silver products can significantly prolong their brilliance and beauty. In conclusion, despite some features and disadvantages, silver remains one of the most attractive materials for creating jewelry. Its brilliance and unique properties make it unique and delightful. Following the rules of care and regular cleaning will help maintain its beauty and resistance to tarnishing, allowing you to enjoy exquisite jewelry for many years. Gold in the jewelry works of Bukhara Gold is one of the most valuable and popular metals used to create jewelry. However, what many people don't know is that gold can come in a variety of colors and alloys, which adds to its uniqueness and variety. When we talk about the color of gold, we usually think of it as a bright and brilliant yellow hue. But in fact, gold can be not only yellow, but also white, red, pink, green and even black. All of these different hues are achieved by adding special metallic alloys to pure gold. White gold, for example, is obtained by adding metals such as nickel, palladium or silver. This gives the gold a silvery hue and makes it feel colder than traditional yellow gold. White gold is often used to create trendy and modern jewelry. Red and pink gold is obtained by adding copper to pure gold. Copper gives gold a rich red hue that can range from soft pink to bright red. Pink gold jewelry is generally considered romantic and feminine. Green gold, known as green gold, is created by adding special alloys such as silver and copper. This color of gold has a special appeal and exotic look, and can be used to create unique and unusual jewelry. There is also black gold, which is obtained by treating gold with special chemicals. Black gold has an elegant and mysterious look and is often used to create stylish and modern jewelry. It is important to note that each color of gold has its own characteristics and requires special care. Some alloys may be softer and more prone to scratching, so it is recommended that you remove 30

your jewelry before playing sports or doing heavy work. In addition, gold in jewelry is represented by various colors and alloys, which give it uniqueness and variety. The choice of gold color depends on your preferences and style, and each of them can be a wonderful addition to your look. Gold is an amazing metal with its own characteristics. One of them is its softness, which is estimated at only 2.5-3.0 on the Mohs scale10. If you touch gold, it will remind us of sensations comparable to touching a fingernail. Another characteristic of gold is its natural sunny yellow color, although it can sometimes have a greenish tinge. But, in addition to its attractive appearance, gold is highly resistant to water, air, acids and alkalis. But the most amazing thing about gold is its malleability and low resistance. After all, just one gram of gold can be rolled into a sheet with a thickness of only 0.0001 mm or create a wire stretched over a distance of 3000 meters. This gives an idea of how flexible and easily machined this metal is. For many centuries, gold has had an irresistible power over people. He was worshiped as the god of the Sun, they fought and killed for him, and also sealed their destinies and promises. And even today, gold continues to be a symbol of wealth and power. However, the scope of gold has expanded over the past century. Today, its use is not limited to jewelry only. Medicine, including surgery and dentistry, has found uses for this noble metal. Gold is used in various medical procedures and implants due to its biocompatibility and antibacterial properties. In addition, gold plays an important role in electronics. Due to its high electrical conductivity and resistance to oxidation, it is used in a variety of electronic components, including contacts and connectors. Therefore, gold continues to delight and amaze us with its unique properties. It has retained its value and importance over the millennia and continues to find new applications, contributing to various branches of science and technology. Yes, gold is used not only in its pure form, but also in the form of alloys with other metals. Pure gold has a bright yellow hue, which is its characteristic feature. However, due to its excessive softness, it is not very suitable for making delicate jewelry. Basically, pure gold products are found in the form of antique jewelry or works of art. However, pure gold can still be used for decorative purposes, such as gold leaf. To give gold the necessary strength and improve its properties, it is often alloyed with other metals. Silver, copper, platinum, palladium, zinc and nickel are the most common gold companions. These metals are added to gold in specific proportions to create alloys with different characteristics. For example, adding copper can give gold a more beautiful reddish hue, while adding silver can make it more durable. Alloys of gold with other metals are widely used in the jewelry industry. They have not only an attractive appearance, but also better strength, which allows you to create elegant and durable jewelry. In addition, gold alloys can come in varying degrees of hardness and color tones, giving jewelers more freedom in their creative process. Definitely, the use of alloying components makes it possible to achieve optimal properties of gold for various purposes. Thanks to this, gold remains one of the most popular materials in the jewelry industry, combining beauty and strength.

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Mohs scale was developed by German mineralogist Friedrich Mohs. It is a scale used by gemologists to classify a gem mineral’s resistance to scratching, or in other words, the difficulty or ease with which one mineral can be scratched by another.

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Gold samples Gold marking is an important indicator that indicates the composition of the alloy and is fixed by a certain code. However, in addition to this information, there is another parameter called gold breakdown. The sample of gold determines the ratio of pure gold to additives in the alloy. This allows you to find out how many milligrams of pure gold are contained in 1 gram of the alloy. Each sample has its own unique characteristic. For example, 585 fineness means that the alloy contains at least 58.5% pure gold. This is one of the most common markings that is often used in jewelry production. The next most popular marking is 750 proof, where the pure gold content is at least 75%. It is higher quality and more valuable. However, there are also rare markings, such as 375 samples. This marking contains only 37.5% pure gold, while the rest consists of copper (48%) and silver (10%). Such an alloy is called a gold-bearing alloy, which quickly tarnishes in air.

Items made from 375 samples are considered low quality due to the high copper content, which causes oxidation and loss of luster. It is important to note that jewelers often do not refer to 375 as "gold" but rather as "gold-bearing copper alloy". This is due to the fact that the content of pure gold in such an alloy is relatively low, and its properties do not correspond to the standard characteristics of gold. It turns out that the marking of gold and the sample are important factors when choosing gold products. They allow you to determine the content of pure gold in the alloy and evaluate its quality. When purchasing gold jewelry, it is useful to pay attention to these characteristics in order to be sure that you are purchasing a high-quality piece. 14k gold is a low-grade alloy that is often used as gold plating. There are various shades in this alloy, depending on the percentage of copper or silver added to it. For example, an alloy with a high copper content will have a reddish tint, while an alloy with a high silver content will have a greenish tint. However, 500 gold castings have their drawbacks. They tend to be patchy and porous, making them practically unsuitable for jewelry such as earrings, rings, or chains. Such products may have low strength and unaesthetic appearance. However, abroad 500 gold finds its application in the manufacture of decorative elements for inexpensive accessories. For example, 32

it can be used to cover parts of eyeglasses, pens or cigarette cases. This allows you to create affordable products with a golden hue, which give a special charm and luxury to such items. Therefore, gold 500, despite its limitations in the manufacture of jewelry, finds its application in other areas. Its use in decorative elements helps to create stylish and attractive accessories that are accessible to a wide range of consumers. 585 is the most popular jewelry alloy containing up to 59% pure gold. The rest consists of silver, palladium, nickel, copper and zinc. This alloy has high strength and hardness, making it less prone to scratches and abrasions than higher grades. One of the benefits of 585 is that it hardly tarnishes over time. On the contrary, jewelry made from this alloy acquires a certain vintage charm, which makes them especially attractive. This can be especially appealing to those who appreciate retro and vintage style in jewelry. Jewelers also prefer to work with 585 because of its versatility. They can use various techniques such as blowing, engraving and weaving to create unique and beautiful jewelry. This alloy lends itself perfectly to processing and forging, allowing craftsmen to turn their creative ideas into reality. Another advantage of 585 is the wide range of shades that can be obtained. This alloy can have different shades of white, red and yellow with varying degrees of saturation. A brighter color indicates that there is more copper in the alloy, but this does not mean that it contains less gold. Thus, 585 jewelries can be rich and vibrant, which makes it attractive to many buyers. As a result, 585 is an ideal choice for those who are looking for durable and beautiful jewelry. Its popularity among jewelers is due to its versatility, the ability to work with various techniques and a wide range of shades. Whether it's a vintage ring or modern earrings, 585 jewelries can be a great addition to any style and express the wearer's personality and taste. Sample 750 is the highest standard in jewelry. Unlike other samples, the content of pure gold here reaches 75%, and the remaining 25% are impurities. That is why the prices for jewelry made of such gold are much higher. This sample is most often used to create exclusive branded products. It offers a wide range of shades including bright yellow, pink, red and white. 750 is also excellent for setting gemstones and making fine, embossed designs. Jewelry made of this gold has medium strength, polishes well, but is prone to scratches. This is especially true for traditional yellow gold. However, white gold, due to its rhodium plating, is more resistant to damage when worn. In addition, 750-carat jewelry is very popular among collectors and jewelry connoisseurs. Their high value and exclusivity make them a desirable investment. Brands that specialize in 750 fine jewelries are known for their impeccable quality and unique designs. It is important to note that when buying jewelry from the 750 sample, it is necessary to pay attention to the certification and labeling of products. This guarantees the authenticity and quality of the gold, and helps to avoid buying fakes. It is also recommended that you take extra care with your 750-carat jewelry to keep it shiny and attractive for a long time. All in all, 750 carat jewelry is the perfect choice for those who value high quality, exclusivity and investment value. Due to their uniqueness and excellent characteristics, they become real works of art that can decorate and elevate any look. Sample 900 is an alloy containing a minimum amount of impurities (approximately 10%) and is considered one of the most expensive. It mainly consists of copper and silver. Products with a breakdown of 900 have a bright yellow color, almost identical to pure gold. This alloy is often used to make coins, bars, and in medical prostheses and crowns. However, apart from this information, there are some more interesting facts about the 900 sample. 33

First, this alloy is highly resistant to oxidation and corrosion, making it ideal for use in jewelry that needs to retain its brilliance and beauty over time. Secondly, 900 proof is also used in the manufacture of some electronic components such as contacts and wires. This is due to the high electrical conductivity of the alloy and its low resistance, which makes it an indispensable material for the transmission of electric current. In addition, a 900 proof can be an attractive investment. Despite the high cost of this alloy, its price on the gold market can increase significantly over time. Many investors purchase 900 gold bars and coins, considering them to be a stable and reliable asset for maintaining and increasing their capital. Thus, 900 is not only a precious alloy, but also a multi-purpose material that finds application in various industries ranging from jewelry to electronics. Due to its unique properties and potential for investment, this alloy continues to be in demand and valuable in the world market. Gold 958 is one of the most precious alloys containing up to 96.3% pure gold. It features a rich, bright yellow color that makes it ideal for creating jewelry such as wedding rings and pendants. Due to the high content of gold, 958 gold jewelry has a beautiful brilliance and an elegant look. However, in addition to gold, the alloy also contains impurities, amounting to about 4%. These additives may include other metals such as silver, copper, or platinum, which give the alloy additional properties and characteristics. For example, copper can improve the strength of gold, while silver can give it a cooler tone. 958 gold not only has a great appearance, but also has a high environmental resistance. It is not subject to oxidation and corrosion, which allows jewelry made of this alloy to retain its original appearance and luster for a long time. In addition, 958 gold has a high malleability, which makes it easy to process and allows complex and unique designs to be created. Due to its outstanding characteristics, 958 gold is in great demand among jewelers and buyers. Jewelry made from this alloy is not only a symbol of luxury and status, but also a unique work of art. Whether it is an engagement ring or a pendant, 958 gold will always attract the admiration and attention of others. Therefore, 958 gold is an ideal combination of high gold content, excellent appearance, stability and ductility. This alloy is an excellent choice for those who appreciate the quality and beauty of jewelry. Sample 999 is pure gold without impurities of other metals. In its pure form, it has a high softness and is subject to rapid deformation, which makes it impractical for jewelers to use. However, there are ways to improve its performance and make it more durable and stable. To do this, jewelers usually add special impurities to pure gold to improve its physical properties. For example, copper can be added to increase the strength and hardness of gold while maintaining its noble hue. Other metals such as silver or platinum can also be used to achieve certain aesthetic effects. There is also a process of coating the surface of gold to protect it from scratches and scuffs. For example, rhodium plating can be applied to the surface of gold jewelry to give it extra brilliance and protect it from oxidation. In addition, pure gold can be used in other areas, including scientific research and industry. For example, due to its high electrical conductivity and chemical inertness, gold is widely used in electronics and the production of electronic components. Pure 999 gold is not an ideal material for jewelry due to its softness, and its properties can be improved by adding impurities or coatings. In addition, it finds application in other industries due to its unique chemical and physical properties.

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Gold color Gold, as we know, can have different shades. Making jewelry from this noble metal requires a meticulous approach, similar to the culinary arts. As in the preparation of any gourmet dish, a variety of ingredients are used in the process of creating a jewelry alloy, in addition to the gold itself. The color and strength of the future product depend on what impurities will be used. The choice of ligature, that is, impurities, plays an important role in determining the shade of gold. Different elements interact differently in an alloy, giving it its own characteristics. Some impurities can make the alloy darker or more brittle if added in excess. Therefore, it is important to find the right ratio of ingredients to provide not only the desired color, but also to keep the alloy suitable for further jewelry work. For example, adding silver to an alloy will create a greenish tint, while copper will give it a pink or red color. The combination of pure gold with palladium will give the alloy a grayish sheen, while platinum will make it white and pure. Interestingly, in addition to color, impurities can also affect other properties of gold. For example, adding a small amount of nickel can make the alloy stronger and more resistant to corrosion. This is especially useful for creating products that are subject to mechanical stress, such as wedding rings. The process of creating gold alloy jewelry is a real art that requires deep knowledge and experience. The combination of various impurities allows you to create unique shades and properties, making each product special and inimitable.

Shades of gold

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Shades of gold in jewelry Red gold, also known as rose gold, gets its characteristic hue from the presence of copper in the alloy. The more copper is added, the brighter and richer the color becomes. If the copper content exceeds 14%, the alloy acquires a bright red hue. However, when a small amount of copper is added, rose gold is obtained. To soften the red color, silver impurities can also be added to the alloy. Red gold is popular among jewelers due to its strength, which allows you to create delicate and airy jewelry without worrying about its deformation. It is usually used to make jewelry without inserts, although it is sometimes also used with semi-precious stones. However, it is important to note that due to the high copper content, gold items can oxidize. In addition, red gold has its own history and symbolic meaning. In some cultures, it is associated with love and passion, which is why it is often chosen as the material for wedding rings or other symbols of love. Also, red gold can be more affordable in terms of price compared to other precious metals, making it an attractive choice for those looking for stylish and quality jewelry. However, it must be remembered that caring for red gold requires special attention. Oxidation and gloss loss can occur over time due to exposure to the environment and chemicals. To preserve its beauty and brilliance, it is recommended to clean regularly and store jewelry in special containers. In conclusion, red gold is an attractive and unique material for jewelry making. It’s beautiful hue and durability make it popular among jewelry lovers. However, it is necessary to remember about proper care and storage in order to preserve its beauty for a long time. White gold. Today, white gold is very popular, especially among lovers of exquisite luxury. They believe that this material best emphasizes the elegance of jewelry and perfectly matches with precious stones, giving them a spectacular look. As for the composition of the white alloy, it contains about 4% zinc, 6% to 20% nickel, and the rest copper. However, if we are talking 36

about platinum, then it is able to give gold a perfectly white hue. Of course, a product made of such an alloy will be much more expensive. In terms of affordability, the most affordable white gold alloy contains nickel, zinc, and copper. Such items are usually plated with a thin layer of rhodium or palladium to create a beautiful and even sheen. However, it is worth noting that such a coating may not be permanent and may wear off over time during wear. But let's look even deeper into the world of white gold. In addition to its popularity in the jewelry industry, this unique substance also finds applications in other industries. For example, white gold is used in some medical devices and electronics due to its unique physical properties. It has high electrical conductivity and chemical inertness, which makes it an ideal material for creating various components. In addition, white gold can be a great alternative to platinum or silver in wedding and engagement rings. It has strength and durability, making it an ideal choice for those who want their jewelry to retain its beauty and brilliance for many years. Thus, white gold is not only a popular material in the jewelry industry, but also a versatile substance that finds application in various fields. Its beauty and strength make it an attractive choice for creating elegant and durable jewelry. Gray gold. In addition to gold, this alloy contains a significant amount of nickel, copper and zinc. Due to this, the gold metal loses its brightness and acquires a pale silver hue. It is important to note that the color of the alloy may fade over time. Greenish tints may appear on the metal surface. This alloy has high hardness and excellent casting properties. In addition, silver alloy is widely used in jewelry production. Due to its strength and durability, it allows you to create exquisite jewelry that retains its original appearance for many years. The pale silver hue of the alloy gives the jewelry a special elegance and sophistication. In addition, the silver alloy also finds application in other industries. Due to its high hardness, it is used to create strong and durable metal structures. Also, its casting properties make it possible to obtain complex shapes and parts, which makes it a sought-after material in the production of various products. However, despite all its advantages, silver alloy requires special care. Due to the tendency to fade, regular cleaning and polishing of this alloy is necessary to maintain its luster and aesthetic appeal. Also avoid contact with harsh chemicals that can damage the metal surface. Therefore, a silver alloy with a high content of nickel, copper and zinc is a durable and aesthetically pleasing material. It finds use in jewelry and other industries, providing strength, durability and the ability to create complex shapes and details. However, to maintain its appearance, regular maintenance and careful handling of products from this alloy is necessary. Yellow gold. Copper and silver are two metals that can be used to create a warm undertone. To achieve this effect, they should be mixed in certain proportions. A ratio of 1 to 2 is usually used, where for every part of copper there are two parts of silver. However, if you want a more saturated shade, you can use equal proportions of copper and silver. This means that for every part of copper there is one part of silver. Such an alloy will help achieve a brighter and more saturated color. The yellow metal offers a wide range of hues, ranging from pale yellow to red through greenish or reddish tones. Depending on the desired effect, you can vary the proportions of copper and silver in the alloy to get the desired shade. It is important to note that as the amount of silver in the alloy increases, it will fade. This means that if you want a lighter shade, then you should increase the amount of silver in the mixture.

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However, if you want a richer and deeper color, then it is better to use more copper. To summarize, the choice of proportions of copper and silver in the alloy depends on the desired result. By using these metals together, beautiful hues can be created that are perfect for a variety of projects and designs. Rose gold is an alloy that is created by adding copper and a small amount of silver to gold. This allows you to achieve a unique pink shade of the metal. The main advantage of rose gold is its relatively low cost, since copper is a cheap component. Thanks to this, rose gold becomes available to a wide range of consumers. The shade of rose gold can vary from almost imperceptible to bright and saturated. It depends on the specific ratio of gold, copper and silver in the alloy. The more copper is added, the richer and brighter the rose gold color becomes. In addition, rose gold is strong and durable, making it an excellent material for making jewelry. It is not subject to corrosion and retains its luster and beauty for a long time. In recent years, rose gold has become especially popular in the jewelry industry. It is used to create a variety of jewelry, including rings, earrings, necklaces, and bracelets. Rose gold gives the jewelry a delicate and romantic look, which makes it attractive to many people. In addition, rose gold can be combined with other metals and gemstones to create unique and stylish designs. It goes well with white gold and silver, which allows you to create interesting contrasts and combinations. In conclusion, rose gold is an attractive and affordable material that allows you to create jewelry with a unique look. Its low cost and durability make it a popular choice for many people who want to add some luxury and elegance to their lives. Green gold, a rare and unique material, has a golden hue, but with a greenish tinge. This special metal is an alloy of gold and silver. Interestingly, by changing the proportions of these two components, different shades of green can be achieved. If potassium is added to the alloy, the gold will take on an olive or pale yellow tint. And another way to get a green color is to add cadmium with copper. An unusual light green shade can be achieved by adding Indian impurities. This opens up great opportunities for creating unique green gold jewelry. Green gold has a long history of use in jewelry. Its unique hue makes it popular with those seeking to stand out and express their individuality. Jewelers often use this material to create exclusive pieces of jewelry such as rings, earrings and necklaces. However, green gold not only attracts attention with its color, but also has a number of other unique properties. It is strong and durable, making it ideal for making jewelry that will last for years to come. In addition, green gold has a high resistance to corrosion, which allows it to retain its brilliance and beauty even after prolonged use. In recent years, green gold has become especially popular in the world of fashion and design. Many famous designers include this material in their collections to give them a special charm and originality. Due to their uniqueness and rarity, green gold jewelry becomes a true work of art that attracts the eye and arouses admiration. Thus, green gold is not only a rare and attractive material, but also a symbol of style and individuality. Its unique properties and ability to create a variety of shades of green make it a desirable material for jewelers and designers. Green gold jewelry will not only emphasize your individuality, but will also become real works of art that will delight you for many years. Blue gold is one of the most unique varieties of gold that attracts the attention of buyers from all over the world. Its exotic color, which is different from the usual yellow gold, gives the jewelry a special appeal and sophistication. 38

However, it should be noted that the share of gold in blue gold is only about 46%. The rest consists of impurities such as indium or gallium. These additives not only give gold a blue hue, but also affect its physical properties such as hardness and melting point. Indium is one of the most common additives in blue gold. It gives gold a deep and rich blue color that can range from delicate blue to bright Turkmen blue. Indium also makes gold softer and more malleable, which makes it easier to process and create jewelry with complex shapes. Gallium, on the other hand, has the property of giving gold a paler and more delicate blue hue. It is used in the production of blue gold to create more delicate and elegant jewelry. In addition, gallium increases the hardness of gold, making it more resistant to scratches and damage. Blue gold is widely used in the jewelry industry to create unique and extravagant pieces of jewelry. It allows designers and jewelers to express their creativity and create truly unique works of art. Due to its unusual beauty, blue gold is becoming more and more popular among jewelry connoisseurs. Therefore, blue gold is an exciting and exotic variety of this precious metal. Its indium or gallium impurities give it a unique blue hue and special physical properties. Due to its beauty and exclusivity, blue gold continues to win the hearts of buyers around the world. Purple gold is a special type of gold often used in jewelry to create a unique decorative effect. Most often, it is used in the form of small flowers or butterflies, which give the jewelry a special sophistication. A feature of purple gold is its distinctive purple tint. This shade is achieved by adding an aluminum impurity, which should be at least 15% of the total composition of the alloy. Thanks to this, gold acquires a unique color and attractiveness. However, it is worth noting that purple gold has increased fragility. It is possible to make one-piece jewelry out of it, but you need to be careful, because with sudden movements it can easily break. Therefore, if you decide to create jewelry from purple gold, be prepared for the fact that it requires careful handling. In addition, there is an alternative use of purple gold. Instead of creating a solid piece of jewelry out of it, you can use it in pendants or earrings as a replacement for a gem. Violet gold can be an excellent base for a frame, giving elegance and originality to a piece of jewelry. Thus, purple gold is a unique material that allows you to create exclusive and unusual jewelry. With its purple tint and particular fragility, it attracts attention and adds sophistication to any decoration. Be careful when using purple gold and enjoy its beauty and uniqueness. Black gold is an unusual shade that is becoming more and more popular. To achieve a black color in a metal alloy, cobalt is added, which oxidizes at high temperatures. Chromium is used to give the alloy a dark brown hue. The process of obtaining black gold is quite expensive. Therefore, jewelry is often coated with a layer of ordinary black rhodium, ruthenium or amorphous carbon. The more intense the black tint, the more likely it is that such a coating will be used on the product. However, in addition to these methods, there are other ways to create black gold. For example, some jewelers use the electrophoresis process, where a black coating is applied to the surface of a piece of jewelry using an electric current. This allows you to achieve a more stable and uniform black color. In addition, black gold can be processed with special techniques to give it a unique look. For example, applying a texture or engraving to the surface of a piece of jewelry can create an interesting contrast with black, making it even more attractive. It is important to note that black 39

gold requires special care and attention. The coating may be subject to abrasion and discoloration with prolonged use. Therefore, it is recommended to avoid contact with harsh chemicals and to clean your jewelry regularly to keep it in its original condition. In conclusion, black gold is a unique and stylish choice for jewelry. Thanks to various methods of obtaining and processing, you can create jewelry with a rich black tint that will attract attention and emphasize your personality.

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IV. Classification of jewelry stones Gemology is a science that deals with the study, classification, diagnosis, evaluation and pricing of precious and semi-precious stones, as well as the processing and creation of new and refined precious and semi-precious stones. She refers to the term "jewelry" as precious ornamental stones, as well as synthesized analogues of natural minerals and chemical compounds that do not exist in nature, such as cubic zirconia and yttro-aluminum granite. Gemstones are minerals that have specific properties due to which they can be used to make jewelry and decorative art products in the jewelry industry. The stone has a number of properties that determine its dignity. These include beauty, which is manifested in its color, transparency, brilliance, play of colors and shades, as well as sparkle and other properties. In addition, an important property is hardness, which determines the durability and ability of the stone to maintain its shape and properties under mechanical stress. Durability also depends on the chemical inertness of the stone. The market value of a stone is determined by its dignity and fashion requirements. The complexity of the processes of mineral formation determines the rarity of finding gemstones in nature. Their insignificant distribution makes them particularly attractive, and the difficulty of discovering and developing deposits determines their high cost. Stones that have all of these properties are considered precious and are the most expensive. If the stone does not fully meet the listed requirements, it is considered less valuable and more common. Depending on various reasons, the requirements for jewelry stones are constantly changing, so their conventionality is very arbitrary. Fashion determines this convention: a stone that has become fashionable increases its price, and accordingly, it is subject to increased requirements for its quality (number of defects, cracks) and color, its uniformity and intensity. The main distinguishing feature of ornamental stones is a beautiful color or intricate decorative pattern. Ornamental stones are usually represented by fine-grained or cryptocrystalline aggregates and can be processed well. For the manufacture of stone-cutting products, polished colored ornamental stones are used. Vases, caskets, sculptures are made from them. Colorful and rare stones are used in jewelry and beads in the form of inserts. Ornamental stones with a variety of shades and decor are used for artistic mosaic work, and more common varieties become a material for architectural and facing work. The classification of precious and ornamental stones in jewelry quality differs from generally accepted mineralogical classifications. Market value is the main value of gemstones, which are also called gemstones. In the 19th century, jewelers divided gemstones into eastern and western, depending on their hardness. There was another classification, which included precious, healing and stones for construction, as well as for the manufacture of statues and vases. The first scientifically substantiated classification of precious and semiprecious stones was proposed by the German scientist K. Kluge in 1860. He divided them into three groups and two groups of true gems and standard gems. In 1902, professor of mineralogy G. Gyurich compiled a classification of precious stones. He divided them into five different classes according to their value. Transparent minerals, which are characterized by high light refraction and are used for making jewelry, make up two classes. Semi-precious stones and colored stones are also included in this classification (two classes). In 1896, M. Bauer developed a new classification of precious stones, which was later expanded and supplemented by Academician A.E. Fersman. In his classification, jewelry and ornamental stones are divided into three groups: 1) precious stones (gems), 41

2) ornamental (colored stones), 3) precious stones of organogenic origin. Group I - precious stones (gems) 1st order: diamond, ruby, sapphire, emerald, alexandrite, noble spinel, euclase. 2 order: topaz, aquamarine, beryl, red tourmaline, blood amethyst, almandine, uvarovite, jadeite, noble opal, zircon. 3 order: 1 - garnet, cordierite, kyanite, epidote, dioptase, turquoise, variscite, green tourmaline. 2 - rock crystal, smoky quartz, light amethyst, chalcedony, agate, carnelian, heliotrope, chrysoprase, prase, semi-opal. 3 - sunstone, moonstone, labradorite, nepheline, sodalite, obsidian, titanite, benitoite, prehnite, andalusite, diopside, scapolite, thomsonite. 4 - hematite, pyrite, cassiterite, quartz with gold. II group - ornamental (colored stones) 1st order: jade, lapis lazuli, glavcolite, sodalite, amazonite, labradorite, rhodonite, azurite, malachite, aventurine, quartzite, rock crystal, smoky quartz, agate and its varieties, jasper, vesuvian, rose quartz, writing granite. 2nd order: lepidolite, fuchsite schist, serpentine, agalmatolite, steatite, selenite, obsidian, marble onyx, datolite, fluorite, halite, graphite, lapis lazuli, smithsonite, zoisite. 3rd order: gypsum, porphyry and partially decorative material - breccias, drain quartzites, etc. The industrial classification of natural jewelry and semi-precious stones, developed by the Research Institute of Jewelery Industry, divides gemstones into four subtypes. Transparent stones, opaque sparkling stones, translucent stones and opaque matte stones with a beautiful color and dense surface texture. Group III - precious stones of organogenic origin, such as pearls, coral, amber and jet. At present, the Bauer-Fersman classification is considered outdated and is not popular with both mineralogists and jewelers. The classification of stones used in jewelry has two types - II and III. Type II includes three subtypes: 1) stones with high hardness (more than 6); 2) stones of medium viscosity and hardness from 5 to 6; 3) small stones of medium hardness. Type III also has three subtypes: 1) stones with a hardness of more than 5; 2) stones with hardness from 5 to 3; 3) soft stones with hardness less than 3. Within each subtype, groups and subgroups are distinguished. This classification has some disadvantages, for example, it combines high value gemstones and low price gemstones. 42

However, it is believed that the classification proposed by Professor E. is one of the best at present. In 1973, Y. Kievlenko proposed a classification system based on Fersman's classification. This system takes into account the market value of colored stones, their use in jewelry and art and stone-cutting craft. The first group is jewelry (cutting, precious) stones. 1st class: diamond, emerald, blue sapphire, ruby. Grade 2: alexandrite, noble jadeite, orange, yellow, purple and green sapphire, noble black opal. Grade 3: demantoid, noble spinel, noble white and fire opal, aquamarine, topaz, rhodolite, moonstone (adularia), red tourmaline. Grade 4: blue, green, pink and polychrome tourmaline, noble spodumene (kunzite, hiddenite), zircon, yellow, green, golden and pink beryl, turquoise, chrysolite, amethyst, chrysoprase, pyrope, almandine, citrine. The second group is ornamental (stone-cutting) stones. Grade 1: rauchtopaz, hematite-bloodstone, amber-succinite, rock crystal, jadeite, jade, lapis lazuli, malachite, aventurine. Grade 2: agate, colored chalcedony, cacholong, amazonite; rhodonite, heliotrope, rose quartz, iridescent obsidian, common opal, labradorite, belomorite. Decorative facing stones, such as jasper, written granite, petrified wood, marble onyx, larchite, obsidian, jet, jaspilite, selenite, fluorite, aventurine quartzite, agalmatolite, patterned flint and colored marble, are opaque and iridescent spars. Diagnostics of jewelry stones is carried out with the determination of their transparency. Transparency refers to the ability of a solid body to transmit light to some extent. Transparency depends on the structure of crystals and the presence of cracks, solid and gas-liquid inclusions in them. The transparency of jewelry stones is determined visually when viewed through the light. Jewelry stones can be divided into several degrees of transparency: - transparent inserts are colorless or slightly colored plates through which you can clearly see the object. - translucent inserts allow you to see objects not quite clearly. Translucent inserts do not allow you to disassemble the item. - Opaque inserts do not let light through. Mamur Fataev has deep experience in classifying precious and semi-precious stones. In his works there is a huge variety of jewelry stones. Shine One of the most important diagnostic features in gemstones is brilliance. Glitter is created by light that reflects off the surface of the stone. The intensity of the brilliance depends on the difference in the speed of light in the air and in the stone. The greater the refractive index, the greater the intensity of the brilliance. Types of gloss can be different: glassy, greasy, resinous, diamond, semi-metallic.

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One type is oily and resinous; light-colored minerals are called fatty, and dark-colored resinous. For most gemstones, color is one of the most characteristic distinguishing features. Gemologists determine the color of the stone visually against the background of white paper. At the boundary of two media, light changes the direction of its movement: part of the light energy returns to the first medium, which is called light reflection; the other part passes through the boundary of the media, changing the direction of propagation. In gemological practice, refractometers are widely used to determine the refractive indices of jewelry stones. These devices allow you to measure the refractive indices of transparent stones that have at least one flat polished facet. The determination of refractive indices on refractometers is based on the phenomenon of total internal reflection at the boundary of two media. An immersion liquid is also used to achieve optical contact when determining refractive indices. This phenomenon, called refraction of light, can be studied using refractometers. The dispersion of refractive indices (light scattering) causes the decomposition of light rays into component parts of the spectrum and the sparkling play of colors of a faceted gem. The color components of a white beam of light are refracted differently in minerals and have different refractive indices. This change in refractive indices with wavelength is called dispersion. The refractive index of the immersion liquid should be higher than the refractive index of the stone and close to the refractive index of the instrument lens. A small number of gemstones (diamond, demantoid, sphene, zircon) are characterized by strong dispersion, which manifests itself in a multi-colored iridescent luster. When determining the quality of jewelry stones, it is necessary to take into account not only the absolute value of the dispersion of refractive indices, but also the color play of cut stones, which is called the dispersion effect. The evaluation of the play of the stone is made visually. An important indicator is also hardness, which determines the ability of a mineral to withstand mechanical stress. The hardness test method used is the scratching method with Mohs relative scale standards, which are portable sets of "hardness pencils". In these sets, pointed pieces of minerals are clamped, which are the standards of the hardness scale. The Mohs scale includes talc, gypsum, calcite, fluorite, apatite, feldspar, quartz, topaz, corundum and diamond, numbered from 1 to 10. Features of diagnostics of gemstones represent more than half of the entire volume of expert work when examining a piece of jewelry. Heavy liquid kits are now used to determine density. The method is based on comparing the density of the gemstone to be determined and the liquid in which it is immersed. Minerals with a higher density sink, while less dense ones float. When the density of the liquid and the stone are equal, the latter remains in suspension. Diagnosis of jewelry stones is difficult due to their identical or similar features. But it is possible to distinguish groups of stones of the same color, such as green, pink, red, blue, etc. To determine the stone, methods based on physical properties and internal features are used. The first task in diagnosis is to determine which mineral type the stone belongs to: corundum (ruby or sapphire), quartz (amethyst or citrine), topaz, tourmaline, spinel, etc. Determining the nature of a stone is possible based on its color, luster and general appearance, but accuracy of determination is achieved only by measuring optical or physical constants using special equipment. Today, there are a huge number of artificial jewelry stones on the market. Synthesis technologies are constantly being improved, but the development of gemological diagnostic methods also does not stand still. Sometimes it looks like a competition: on the one hand, manufacturers of synthetic stones strive to make them as similar as possible to natural ones, and on the other hand, gemologists develop new identification methods to distinguish natural stones from synthetic ones. 44

Conventional crystallization processes based on heterogeneous chemical reactions underlie the production of artificial and synthetic jewelry crystals. As a result of these processes, single crystals or their polycrystalline aggregates are formed. Crystallization can occur both as a result of the transformation of the initial solid phase, and by the formation of a solid phase from liquid and gaseous. In order for crystallization to begin, the initial phase must become saturated, that is, supercooled. There are many classifications of methods for the synthesis and growth of crystals, which are based on the phase state and component composition of the initial medium, as well as on the nature of the driving force of the process. Supersaturation in the practice of crystal synthesis and growth is usually set by creating and maintaining a gradient of temperatures, pressures, and concentrations in the system. Depending on these factors, the following methods can be distinguished: 1. Growing crystals from stoichiometric melts 11. Mainly the temperature gradient is used as the driving force of the process. Crystals are grown from solutions, and crystallization occurs due to the creation of a concentration gradient at the crystal-solution interface. 2. Crystals are also grown from the gas phase, where the crystallization process is carried out due to the presence of a pressure gradient. Slight differences from natural stones that characterize synthetic stones are due to the specific conditions of their formation (crystallization), but basically they have the same properties as their natural counterparts. The slow growth of crystals in nature occurs under pressure from hot aqueous solutions or molten magma. Also important is the presence of various chemical compounds that, under certain conditions, interact and form different minerals. Therefore, when examining a natural stone, one can notice small inclusions of other minerals that formed with it, or traces of the surrounding liquid in which it was formed. In contrast, synthetic stones grow in more "pure" chemical conditions, so the only extraneous crystalline inclusions may be compounds similar in composition to the main crystal. At the beginning of the 20th century, artificial rubies and sapphires, created by the French scientist Verneuil, appeared on the market. He developed a special furnace in which pure aluminum with a small amount of metallic dyes is passed through an oxy-hydrogen flame and crystallized as boules. Synthetic analogues have the same crystal lattice and chemical composition as natural stones. Therefore, the use of tools commonly used to identify natural stones to identify synthetic counterparts does not make sense. However, there are exceptions to this rule when crystals are grown on a seed of natural minerals with characteristic inclusions. Methods for identifying differences between natural and synthetic gemstones. The production of large-sized synthetic stones in a short time is possible thanks to this process. Fortunately, the ease of distinguishing natural minerals from artificial ones is due to the speed of this process. Some features of the growth and internal structure of natural minerals used in jewelry and synthetic analogues reflect differences in formation conditions. This difference manifests itself in the zonality of the crystals and in the nature of the distribution of color and inclusions. Over time, new methods of producing synthetic stones appear, which present problems even for experienced gemologists. However, there are not many such stones on the market. The exception is when crystals are grown on a seed from a natural mineral with its characteristic inclusions. Synthetic stones have essentially the same properties as their natural counterparts, with minor differences due to the

11

Stoichiometry (from the Greek stoicheioп - “original, basis, element” and metreo - “I measure”) - in chemistry, the study of quantitative relationships between the masses (volumes) of reacting substances (simple and complex).

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specific conditions of their formation (crystallization). Crystals in nature grow slowly under pressure from hot aqueous solutions or from molten magma. When examining a natural stone, one can observe small inclusions of other minerals or traces of the surrounding liquid in which it was formed. This is due to the presence of many chemical compounds that can, under certain conditions, interact and form various minerals. Gems of Uzbekistan Uzbekistan, located in Central Asia, is a country with rich natural resources, which play an important role in the development of its economy. This amazing region is known for its numerous minerals that are mined and used in various industries. One of the main sectors of the economy of Uzbekistan is the mining industry. Semi-precious minerals such as tourmaline, amethyst, agate and others are actively mined here. These valuable stones are used in jewelry production to create unique pieces that are popular both in the domestic and international markets. In addition to semi-precious minerals, Uzbekistan is also a major producer of non-ferrous metals. Metals such as copper, lead, zinc and aluminum are mined here. These metals are widely used in industry to produce a variety of products, ranging from electronics and automobiles to building materials. The jewelry industry of Uzbekistan is based on the rich reserves of gold and silver in the country. Gold, especially, is one of the most valuable resources that are mined here. Uzbekistan is one of the largest producers of gold in the world and its precious metal is widely used in jewelry. In addition, it also plays an important role in the jewelry industry, and it is mined in significant quantities in the country. In addition to precious metals, Uzbekistan is also known for its ornamental stones and artificially grown cubic zirkonia. Ornamental stones such as jasper, labradorite and amazonite are used to create jewelry and souvenirs. Cubic Zirconia, artificially created stones, have a high degree of purity and brilliance, and are widely used in jewelry as a substitute for natural gems. Thus, Uzbekistan is a country with rich natural resources that contribute to the development of its economy. Thanks to the extraction of semi-precious minerals, non-ferrous metals, gold, silver, gemstones and cubic zirkonia, the country strengthens its position in the world market and provides jobs for many people. Diamonds of Uzbekistan: Wealth that has not yet been discovered. Natural diamonds are not mined in Uzbekistan, but the history of the search for these gems in this country goes back several decades. Soviet geology at one time made significant efforts to find deposits in a region that for a long time was considered unpromising. However, the researchers found interesting signs of the presence of diamonds in the Southern Tien Shan region. It turned out that there is a large belt of rich diamond-bearing rocks. This discovery pointed to potentially significant diamond reserves in the country. Since then, research has continued, and geologists have discovered about 20 promising areas where exploration can begin. This opens up new horizons for the treasures of Uzbekistan and can lead to economic growth and development of the country. However, it is worth noting that the process of diamond mining is complex and requires significant investments. It is necessary to develop effective technologies and infrastructure for the extraction and processing of diamonds. In addition, it is important to take into account the environment and nature in order to minimize the negative impact on the ecosystem. Uzbekistan also seeks to develop jewelry tourism to attract more people interested in gems. The country can offer not only diamonds, but also other valuable stones such as emeralds, rubies and sapphires. Uzbekistan's wealth of natural resources makes it a potential destination for jewelry lovers and collectors. However, Uzbekistan has the potential to become an important player in the global market for diamonds and other precious stones. Proper development and extraction of these resources 46

can bring significant economic benefits and contribute to the development of the country as a whole. Uzbekistan is known for its rich mineralogical diversity. In various regions of the country you can find deposits of multi-colored jewelry and ornamental stones. For example, in the area of the Pskem Range there are deposits of amethyst, which is a variety of purple, blue and lilac quartz. These stones are of great value to collectors because they are not found very often. Another valuable mineral that is mined in this region is rock crystal. This transparent stone, which is presented in the form of crystals or fused brushes, is widely used in jewelry. It can be used as an independent insert in gold or silver jewelry, as well as in combination with other colored stones. Rock crystal is known for its clarity and clarity, making it particularly attractive to jewelers and collectors. In addition, deposits of dumortierite, a valuable opaque mineral with a pronounced pleochroism effect, can be found in Uzbekistan. This stone has various shades, ranging from light blue to brown-red. However, due to the complexity of its cutting, which requires careful and lengthy work by the jeweler, dumortierite jewelry is expensive. Uzbekistan is also famous for finding a rare mineral that belongs both to the class of silicates and complex sulfates. This mineral, known as thaumasite, is colorless to white with a translucent effect and a vitreous luster. Thaumasite is of particular value to collectors, as its unique chemical composition makes it a rare and unique find. Thus, the Uzbek lands are rich in a variety of jewelry and ornamental stones, including amethyst, rock crystal, dumortierite and thaumasite. These stones are not only valuable for collectors, but are also used in the creation of fine jewelry that emphasizes the natural beauty and richness of Uzbek nature. Uzbekistan was famous for its high quality turquoise, which was the main supplier of this precious stone for the jewelry industry of the USSR since the 60s of the 20th century. This stone, with its characteristic blue-green hue, was known as "royal blue" and was considered a real treasure. However, over time, turquoise mines in Uzbekistan and around the world were depleted, which led to a decrease in the production of this valuable gem. Currently, many turquoise mines in Uzbekistan are closed, as their reserves are depleted. This has led to the fact that most of the turquoise on the world market is synthetic. However, even among synthetic samples, those that are as close as possible to the natural "royal blue" color are evaluated. These synthetic variants have their value among collectors and jewelers. However, even with the disappearance of the "royal blue" turquoise, Uzbek stone workshops continue to work with other types of this stone. For example, small pale turquoise nuggets can be ennobled and used in jewelry. Such turquoise is called restored or pressed, and it also finds its fans in the jewelry industry. Uzbekistan is also famous for the variety of other precious and semi-precious stones that are mined in the region. In the Chatkal-Kurama and Kyzylkum12 regions you can find gems of different shades, which are popular both among jewelers and collectors. Jewelry stones such as moonstone, amethyst, tourmaline and others are mined in these regions and find their use in jewelry and jewelry. In addition, Uzbekistan is considered a promising region for finding diamonds. Although precious diamonds have not yet been mined in this country, geological studies and the discovery of diamond-bearing mines indicate the potential for future mining of this gem. This could lead 12

Kyzylkum (Uzb. Qizilqum, Karakalp. Qızılqum, Kaz. Kyzylkum, Turkmen. Gyzylgum) is a sandy and stony desert between the Amu Darya and Syr Darya rivers, in Uzbekistan, Kazakhstan and Turkmenistan.

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to a new stage in the development of the precious industry of Uzbekistan and an increase in its role in the global precious stones market. In addition, although the disappearance of the turquoise mines in Uzbekistan has left its mark on the country's jewelry industry, it continues to develop and seek new opportunities in the mining and processing of other precious stones, making Uzbekistan an interesting destination for both jewelers and collectors, as well as geologists searching for new diamond deposits.

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V. Auxiliary materials Auxiliary materials play an important role in various processes associated with the processing and use of metals. One such material is boric acid13. The chemical formula of this substance is H3BO4, and the acid itself is a white crystalline compound. Boric acid is a weak acid and is highly soluble in hot water. As it cools, it crystallizes, making it suitable for use in a variety of processes, including the preparation of flux for soldering precious metals. In addition to boric acid, an auxiliary material widely used in metal processing is citric acid. Its chemical formula is C6H8O7 and the acid itself is a water-soluble solid that forms white crystals. Citric acid is used to whiten metal after soldering. When heated, it dissolves flux residues and oxides, giving the metal a fresh and clean look. It is also necessary to mention borax - sodium salt, which is also used in metal processing. Its chemical formula is Na2B4O7×10H2O. Borax is an integral part of many metal-related processes and is used as an additive to impart certain properties to materials. Thus, auxiliary materials such as boric acid, citric acid and borax play an important role in the processing and use of metals. They have certain properties that make them an integral part of various processes. Thanks to these materials, you can achieve optimal results when working with metals and ensure their quality use. Tetraboric acid is widely used in jewelry technology. Its molten form is capable of dissolving metal oxides. As it cools, large transparent crystals form. One of the applications of this acid is the cleaning of alloys in metal smelting. However, it can also be used as a standalone flux for brazing non-ferrous metals such as brass, cupronickel, copper and nickel silver. In jewelry art, especially in the filigree technique, a mixture of calcined and ground borax in a mortar, as well as crushed silver solder is often used. In addition, paste or kit is used to fix jewelry parts. The most common materials used in jewelry making include precious metals such as gold and silver. However, in order to create strong and durable jewelry, it is necessary to use additional materials that provide stability and protection to the shape of the product. One such material is shellac, which is a natural resin. Shellac is used to temporarily fix small parts when filing and drilling. It dissolves in technical alcohol, forming a strong and reliable bond between parts. Refractory materials are used to ensure high temperature resistance during soldering and melting of metals. They are composed of asbestos, refractory clay and graphite. Asbestos, due to its fibrous structure, is able to withstand temperatures up to 600-800°C. Refractory clay and graphite are also used in the process of making crucibles for melting metals. These materials provide reliable insulation and protection against high temperatures, preventing distortion of the shape of products. Thus, the use of various materials in jewelry production plays an important role in maintaining the shape and quality of products. The strength, durability and aesthetic appeal of jewelry depend on the correct choice and use of these materials. When melting metals, it is important to use a special tool to ensure uniform heat distribution and mixing of alloys. In this case, for these purposes, a quartz glass rod14 is used, which has high heat resistance and is able to withstand extremely high temperatures up to 1100 ° C. This 13

Boric acid (from Latin acidum Boricum, orthoboric acid, chemical formula - H3BO3 or B(OH)3) is a weak chemical inorganic acid corresponding to the highest oxidation state of boron (+3). 14 Quartz rods, or rods as they are also called, are one of the most widely manufactured quartz glass derivatives.

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allows not only successful melting of metals, but also guarantees the safety and efficiency of the process. Quartz glass is an ideal material, as it is not only resistant to high temperatures, but also chemically inert, which avoids unwanted reactions with metal alloys. Due to these properties, the quartz glass rod has become an indispensable tool in the metallurgical industry, ensuring high quality and stability in the metal smelting process.

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VI. Basic technological operations for making jewelry by hand First, the master begins to create a sketch or model of the future product. Here it is important to show your creative thought and take into account all the details so that the product is not only beautiful, but also functional. After that, the manual work process begins. The craftsman uses various tools such as nail files, tweezers and blowtorches to create the shape and texture of the piece. He must be very careful and attentive so as not to spoil the precious material. The final stage is finishing and polishing. The master uses special tools and techniques to give the product shine and radiance. This is a very important step, because it is thanks to the finish that the piece of jewelry becomes truly complete and attractive. Thus, the basic technological operations of making jewelry by hand is a complex process that requires not only skill and technical skills, but also a creative approach. Each product is a small masterpiece, created with love and diligence. Preparing operations are an important stage in the process of making jewelry. One of these operations is markup. Marking is a technological procedure, as a result of which the drawing of a future product or its individual part is transferred to the material. The quality of subsequent processing and the final product depends on how correctly the marking is done. Even small inaccuracies and errors in the markup can lead to distortion of the elements of the drawing and disrupt the form and content of the artistic intent. Therefore, it is important to pay due attention to the markup and carry it out with maximum accuracy. There is no room for error when it comes to creating jewelry masterpieces. Marking a product is a process that includes several stages. At the beginning, the product sample being created is prepared by carefully drawing it on graph paper. This allows you to get the exact dimensions and shape of the product. Further, before marking, the material for the manufacture of the product must be ready. For example, if it is metal, it must be annealed so that the marking lines are more visible on its surface. In addition, the workpiece must be free from defects such as cracks, dents or pits. Only then can you start marking the product. There are several ways to markup, one of them is drawing lines. But other methods can also be used, depending on the material and marking requirements. Thus, the marking process is a responsible and important stage in the production of a product, which requires precision and attention to detail. Creating designs and geometric shapes on metal is a fun process that can be done in a variety of ways. One way is to use a scriber or a marking compass to create contour lines and markings on the workpiece. Another way is to transfer the design from tracing paper to a metal surface using wax, carbon paper, a thin layer of gouache or gouging. But what do these marking lines mean and how do they help in the jewelry making process? Contour lines play an important role, defining the contour of the future part and allowing you to transfer the ornament to the product. They also show the margins of the work, helping the jeweler to understand what part of the metal will be cut or turned. In addition to contour lines, there are also control risks. They are drawn parallel to the contour lines and serve to check the correctness of processing. The control marks allow the jeweler to make sure that all the processed areas correspond to the specified sizes and shapes. As such, they are an essential tool for quality workmanship and ensure that the piece of jewelry is perfectly crafted.

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As a result, the creation of patterns and geometric shapes on metal requires precision and attention to detail. Scriber, compasses, tracing paper, wax, carbon paper, gouache and gouging all these tools and techniques help the jeweler to realize his ideas and create unique jewelry. In the individual and small-scale production of jewelry, marking is widely used, which allows you to get parts of a certain shape and required sizes, as well as to rationally use the material. To do this, auxiliary lines mark the axes of symmetry, the centers of the radii of curvature and the marking of the axial lines for stones. However, it must be borne in mind that after the manufacture of parts, it may be necessary to correct their surface. For this, an operation called metal dressing is used. Its essence lies in the compression of convex metal in order to correct the curvature of the surface and eliminate defects such as concavity, convexity, waviness and warping. Metal dressing is an integral part of the jewelry processing process, because a high-quality surface is one of the key criteria for their evaluation. During the straightening process, the master uses special tools such as hammers, chisels and molds to achieve the desired result. In addition, metal dressing may be necessary not only to correct defects, but also to create special effects and design solutions. Craftsmen can use this technique to give an item a particular shape, texture, or dimension. Thus, the marking and straightening of metal are important steps in the process of making jewelry. They allow you to create parts of a certain shape and size, correct the surface and eliminate defects, as well as give the product a special look. Editing of metal is carried out manually, using special tools and fixtures. However, manual dressing has its limitations and can only be applied to small gauge wire. The quality of such manual editing usually leaves much to be desired. To cope with this problem, editing with the help of tools and devices has been developed, which is divided into several types: editing sheet, tape, wire and tubular material. For example, for straightening sheet and strip material, special straightening plates and hammers with rectangular and round shapes are used. This allows for more accurate and efficient dressing, ensuring high quality and precision. In addition, such editing allows you to work with materials of various thicknesses and shapes, which expands its scope. The choice of one or another method of straightening metal depends on its size, type and condition. To begin with, before straightening, the metal should be annealed to make it more pliable. Then the process of editing the working part of the striker begins. To make it smooth and without damage, it is necessary to carry out several operations. The first step is to straighten a wide blank sheet. It is corrected by light tapping of the hammer, starting from the middle and gradually moving towards the edge. Thus, the uniformity and smoothness of the surface is achieved. Next, straightening wire and tubular material carried out in several ways. One of them is stretching. To do this, one end of the workpiece is clamped in a vise, and the other is pulled out with pliers. Another way is to pull through the die hole. It also applies pulling with pliers around the mandrel. It is important to note that the metal can be straightened both in a cold and heated state. The choice of method depends on the size and type of material. Cold dressing is typically used for finer parts, while hot dressing allows for better control of the process and the desired shape. Thus, metal straightening is an important process in production that requires certain skills and tools. It allows you to create smooth and defect-free parts, ready for further use. 52

Metal bending is one of the main operations for processing metal blanks. This process allows the material to be bent into shape according to the requirements of the drawing. The main purpose of bending is the deformation of the metal under the influence of external forces. During the bending operation, the upper layers of the metal are stretched, and the inner layers are compressed, which creates the necessary bending stresses. It is important to note that these stresses must exceed the elastic limit of the material, and the deformation of the workpiece must be plastic. This allows you to provide optimal conditions for the successful completion of the bending operation. The use of metal bending in manufacturing has many advantages. Firstly, it allows you to create blanks with a variety of curves and shapes, which expands the possibilities of design and architectural solutions. In addition, metal bending makes it possible to achieve high bending accuracy, which is especially important in the production of parts with technical requirements. In conclusion, metal bending is an integral part of the processing of metal blanks. It allows you to create complex curved shapes, while providing the necessary stresses and deformations. Metal bending is an important tool in production, which allows you to achieve high precision and quality of the final product. In order to successfully machine a workpiece, a heat treatment, known as annealing, must be carried out. Annealing is the process of heating a metal to a certain temperature and then cooling it to achieve the desired softness. Only in this case, the workpiece will be able to retain its shape after the load is removed. Depending on the type of metal, the annealing temperature may vary. For example, for brass it is about 650 degrees, and for cupronickel - about 700 degrees. Cooling can take place in air or in water. However, after heat treatment, it is necessary to bend the workpiece during assembly operations. This is done by hand using various fixtures and tools. Bending allows you to create complex product profiles and give them the desired shape. It is important to consider that the bending process requires certain techniques and skills in order to avoid deformation of the workpiece or damage to the material. Thus, heat treatment and bending of blanks are important steps in the production of metal products. They allow you to achieve the desired softness and shape of the workpiece, which ultimately determines the quality and functionality of the finished product. When bending a metal workpiece, it is necessary to use special mandrels and plates with a bending chute. This allows you to ensure the correct shape and bending of the part. However, it is important to take into account not only the tools, but also the dimensions of the workpiece itself. Determining the dimensions of the workpiece is an important step in the bending process. To do this, it is necessary to calculate the length of the workpiece, taking into account the radii of all bends. It should also be noted that for parts that are bent at a right angle without rounding, a bending allowance must be provided. It is recommended that the allowance be 0.6-0.8 mm from the thickness of the metal. An important point in bending metal is to take into account the elasticity of the material. With plastic deformation and subsequent removal of the load, the bending angle may change. Therefore, it is necessary to take this factor into account and provide for possible adjustments after bending the workpiece. Thus, bending metal blanks requires not only the use of special tools, but also taking into account the dimensions and elasticity of the material. This allows you to get a high-quality and correct shape of the part. 53

In the manual processing of metal, cutting the material of the blanks is becoming more and more in demand. Various hand tools are used for this task, such as guillotine shears, hand shears for metal, and needle nose pliers. Depending on the shape and size of the workpieces, the appropriate tool is selected. Guillotine shears are used for cutting sheet metal products with a thickness of 1.5 to 3.5 mm. This tool provides fast and accurate cutting, allowing you to create various parts and features. For thinner material, such as flat products up to 0.8 mm thick, hand shears are used. They allow you to make precise and neat cuts without damaging the material. Such a tool is often used in the manufacture of hinged tubes, sides and other metal blanks. Do not forget about cutting strips of solder. Manual metal shears also do an excellent job of providing clean, even cuts. This is especially important when working with such parts, where it is necessary to accurately observe the dimensions and shape. Thus, cutting metal during manual processing in a training workshop requires the use of different tools, depending on the thickness and shape of the workpieces. Guillotine shears, hand shears and needle nose pliers all play an important role in creating quality metal parts and products. Rolling and rolling of metal are important processes in the processing of metal blanks. They allow you to change the shape and dimensions of the metal using pressure and cutting tools. One of these tools are needle-nose pliers, which are used to cut wire, pieces of solder, and small pieces of metal. The essence of the operation of cutting metal with needle nose pliers and hand scissors is that the wire or strip metal is divided into parts using two cutting knives moving towards each other. This operation requires precision and skill to get the desired result. Metal rolling is a process of continuously changing the shape of a metal along its entire length with the help of pressure. This process makes it possible to obtain various shapes and sizes of metal products, ranging from simple strips and wires to complex pipes and profiles. Rolling, in turn, is the rolling of a certain section of the workpiece, which makes it possible to achieve even greater accuracy and quality of processing. It is important to note that metal rolling and rolling are an integral part of the metallurgical industry. Through these processes, metal products can be created with high precision and quality, allowing them to be used in a variety of industries, including automotive, construction and energy. The process of rolling metal allows you to obtain blanks of the desired shape and profile, and the cross section of the rolled metal is called the profile. However, rolling not only has this function, it also improves the mechanical properties of the metal, making its structure denser and fine-grained. Rollers are used in the training workshop to perform rolling and rolling operations. There are two types of rollers - mechanically (or electrically) driven and manual. Mechanically driven rolls provide automation of the rolling process, which improves work efficiency and reduces the physical burden on workers. However, manual rollers are still widely used in some cases, such as for small volumes of work or in situations where there is no electricity. In addition, manual rollers can be useful in teaching and training students in educational institutions. Thus, rollers are an integral part of the rolling and rolling process, and their use depends on the specific conditions and requirements of the production.

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In the process of working with rollers, consisting of a support table, rotating rollers and a gap adjuster, it is possible to make some changes. For example, new sentences can be added to explore their function and application in more detail. Rolls with a smooth surface are designed for rolling various materials such as sheets, ingots, rods and wires in order to flatten them and bring them into the desired shape. They allow you to perform various operations with metal, such as leveling, thinning and reshaping. However, it is important to note that in addition to smooth surface rollers, there are also profiled rollers. They are cylinders with grooves of various profiles around the circumference. Such rollers allow rolling material with a given profile, which is necessary for the production of various parts and products. Profile streams, which are formed on the rolls, are cuts of various shapes. They serve to create a gap-passage through which the rolled metal passes. A variety of shapes of profile streams makes it possible to obtain various types of profiles on the rolled material. Thus, rollers are an important machine tool in the process of metal rolling, their diversity and functionality make it possible to obtain materials with different properties and shapes, which opens up wide possibilities for application in various industries. In the process of rolling metal blanks, a variety of equipment is used. Common forms of blanks are square, round and semicircular. Rolling equipment consists of rotating rolls that pass the billet between them. As a result of the friction that occurs between the workpiece and the rolls under the action of pressure forces, the workpiece is compressed. The gap between the rolls must be less than the thickness of the original workpiece to ensure proper reduction. After each pass of the workpiece between the rolls, its thickness decreases, and the length increases. In this case, a slight expansion of the workpiece along the section is possible. Thus, rolling metal blanks allows you to get their desired shape and size. Hardening of metal is a process that allows you to increase its strength and reduce its ductility. To do this, the metal workpiece is subjected to machining - turning the rolls clockwise by 90°. This operation is carried out several times until the required thickness of the workpiece is reached. However, such a long mechanical impact on the metal can cause its deformation and hardening. To prevent cracking of the metal and relieve the load, the workpiece is subjected to heat treatment in a muffle furnace. Heat treatment, or annealing, allows the metal to return to its original structure. As a result of this process, the metal again becomes elastic and has the necessary flexibility and ductility. Thus, work hardening and subsequent annealing are important stages of production, which make it possible to give the metal the desired physical properties and guarantee its strength and durability. Rolling of metal in profile rolls with a square section is an important process in metallurgy. However, to achieve a high-quality result, it is necessary to correctly configure the sequence of operations. We start by spreading the rolls apart to create a gap large enough for the bar to pass freely. Then, while pressing the rolls, we proceed to the rolling itself with little effort. Interestingly, in this case, two ribs are first crimped, and then we turn the workpiece over and crimp the next two. This sequence is due to the shape of the windrows, which is diamond-shaped. It is important to note that during the primary reduction, the excess metal is stretched in length and slightly squeezed out into the gaps between the rolls. This allows you to get more accurate dimensions and a smooth surface of the rolled metal. As a result, the process of rolling metal in 55

profile rolls with a square section requires fine tuning and craftsmanship in order to achieve high quality and accuracy of the rolled material. When rolling horizontally located edges of the bar, we observe the form of sagging. However, if we turn the bar by 90° and roll it again, then the influx of metal from the ribs will return to the total mass of the rolled product. This process is repeated until the rod can freely pass into the stream. Then we reduce the gap again and continue to roll the bar until the desired size is reached. It is important to monitor the condition of the metal and carry out heat treatments such as annealing to improve its properties. Thus, bar rolling is a complex process that requires attention and precision. Basic mounting manipulations drilling In the work of making jewelry, one of the key tasks is to obtain various holes in the details. To perform this operation, a special tool is used - a drill, which allows you to form a hole in a solid material. The technological process of drilling is carried out with the help of rotational and translational movements of the tool relative to its axis. These movements are created using various hand tools. They allow you to control the depth and diameter of the hole, and also ensure the accuracy and quality of work. It is important to note that choosing the right drill bit and the optimal sharpening angle is critical to the successful completion of a drilling operation. Incorrect tool selection can result in material distortion or unwanted holes. In addition, to achieve optimal results, it is necessary to take into account the characteristics of the material to be drilled. Different materials require different approaches and drilling parameters. For example, when working with hard metals, it is necessary to use coated drills to increase the strength and wear resistance of the tool. Thus, the drilling operation is an integral part of the jewelry making process. The right choice of tool, the optimal sharpening angle and taking into account the characteristics of the material allow you to get high-quality and durable holes, which ultimately affects the overall quality and appearance of the products. Holes are made in the material using special tools such as a jeweler's drill or a power tool such as a drill. To ensure high-quality drilling, it is necessary to properly prepare the drilling fixture and the product itself. First, choose the correct drill size and secure it in the drill chuck or collet holder. Then the rotation of the drill is checked at idle speed of the tool in order to achieve a smooth rotation without the slightest beat. When a hole needs to be made on a product, a special tool is used - a core or a steel rod with a blunt end. This tool allows you to make holes accurately and without damaging the material. It is important to note that the preparation of the drilling fixture and the correct choice of tool are critical to successful drilling. For more efficient work with the material, you can use the deepening technique. A small dimple will prevent the drill from slipping on the surface and provide more accurate drilling. In addition, to securely fix the workpiece, you can use a special wooden stand with fixing resin or a horizontal vise. When everything is ready, you can start drilling. Set the drill tip into the core hole and start drilling the hole. It is important to remember that the axis of the drill is perpendicular to the plane of the workpiece, and feed the drill with light pressure. During operation, regularly check that the drill is in the correct position and remove it from the hole to remove accumulated chips with a brush. 56

Keep in mind that applying too much pressure to the drill may break the drill or damage the material. Therefore, it is important to maintain balance and not press too hard. It is also worth considering that different materials require different drilling speeds and drill feeds. Before starting work, it is recommended to familiarize yourself with the manufacturer's recommendations and conduct test drilling on a sample of the material. Before each pass, the drill is lubricated with wax to avoid overheating of the metal. But what happens if you don't follow this simple procedure? Pressure and deflection to the side are what can lead to breakage of the drill. When a drill is not lubricated, the friction between its surface and the metal increases, which can lead to irreparable damage. Breaking a drill bit can be not only expensive, but also dangerous, especially if bit parts fly out in different directions. Therefore, you must always remember to lubricate the drill before starting work. Sawing Sawing with a jigsaw is one of the original operations in handmade jewelry making. This process not only helps to create the shape of the product, but also allows you to cut out ornaments and stone nests, as well as align the cuts of patterns in hard-to-reach places and perform other cutting work. Jigsaw files are special tools of a certain length and shape. They are equipped with cutting teeth that allow you to easily penetrate the metal and create the desired shape. The movement of the cutting blade (file) is carried out in a reciprocating way, which makes it possible to accurately control the cutting process. One of the advantages of jigsaw cutting is its versatility. This method is suitable for working with a variety of metals, including gold, silver, platinum, and even hard alloys. With the jigsaw, jewelers can create unique and intricate patterns that give pieces a special charm and personality. It should be noted that sawing with a jigsaw requires certain skills and patience. Jewelers must be careful and careful to avoid errors and damage to the material. In addition, choosing the right file and the right cutting technique also play an important role in creating a quality piece of jewelry. In general, sawing with a jigsaw is an important and integral step in the jewelry making process. It allows jewelers to express their creativity and skill, creating unique and inimitable jewelry. A hardened wire of rectangular cross section with a slanted notch on one of the edges is used to work with a jigsaw. The jigsaw performs a downward movement with pressure, called a working stroke, and an upward movement without pressure, called an idle stroke. The vertical position of the jigsaw (handle down) allows you to work comfortably, so the file is fixed so that the cutting teeth are directed down towards the handle. In the state of operation, the file is tensioned with a deviation from the axis of about 3 mm. The weak tension of the file does not provide an accurate cut along the markup, while the strong tension of the cutting blade makes it difficult to freely maneuver during work. It is important to consider that the choice of the correct file tension affects the quality and accuracy of the jigsaw. If the saw blade is not tight enough, it can jump off the track, resulting in an uneven cut or even breakage of the saw blade. On the other hand, excessive tension can wear the saw blade and reduce its cutting properties. Therefore, it is important to find the optimal tension that will provide stability and control when working with a jigsaw. In order to achieve the correct tension on the file, a special tensioning device should be used, which allows you to adjust the degree of tension. Before starting work, it is necessary to 57

check and adjust the tension of the file in accordance with the requirements of a particular task. It is important to remember that the tension of the file can change during operation, so it should be checked and adjusted periodically during operation. So, the correct tension of the file is a key factor for the successful operation of the jigsaw. It provides stability, precision and control when cutting, and extends saw blade life. Therefore, it is necessary to pay due attention to the selection and adjustment of the tension of the file before starting work and during its implementation. When cutting curved cuts in small areas, it is important to take into account not only the accuracy and accuracy of the work, but also to choose the most effective method. One such method is the use of a special tool designed to perform such tasks accurately and quickly. It may seem to novice craftsmen that cutting curved cuts in small areas is a difficult task that requires a lot of experience and skills. However, with the use of specialized tools, this process can be greatly simplified and accelerated. One such tool is an electric jigsaw, which allows you to make precise and beautiful curved cuts on various materials, from wood to metal. Due to its compactness and maneuverability, the jigsaw allows you to work even in narrow and hard-to-reach areas. When choosing a jigsaw for cutting curved cuts in small areas, you should pay attention to its power, speed control and the presence of special nozzles and accessories. These characteristics will allow you to choose the tool most suitable for a particular task. Thus, cutting curved cuts in small areas is a process that requires not only skill and experience, but also the use of specialized tools. There are various options for jigsaws on the market, allowing you to achieve high accuracy and quality of work. Sawing is a cutting method that is carried out by removing the required layer of material from the surface of the workpiece using a multi-blade cutting tool, such as a file or needle file. Filing is one of the main technological operations used throughout the entire jewelry manufacturing process. It is used to level the surface of a product or workpiece, to give the required shape and size to the elements of a piece of jewelry, as well as to fit parts to each other during installation. Files perform various tasks, such as processing planes and curved surfaces with grooves and grooves, holes of various shapes, as well as surfaces located at different angles and other tasks. Small allowances are left for filing, about 0.5 mm. Depending on the purpose, the files are divided into general, special purpose, and corrugated. Soldering is the process of making permanent joints by using a metal alloy that has a lower melting point than the materials to be joined. The connecting material that is used in soldering is known as solder. The essence of soldering is that the molten solder wets the surfaces to be joined, and partially connects to them by diffusion. When cooled, a strong bond is formed between these surfaces. As a result of diffusion, the solder is connected to the base metal. Text properties such as color, plasticity and hardness can be changed. The diffusion penetration of metals depends on the soldering mode (temperature, heating time) and the gap between the soldered metal sections. On refractory asbestos, ceramic or heat-insulating vermiculite boards, soldering is performed. When mounting jewelry using soldering, it is necessary to take into account the strength, tightness and cleaning of the surfaces to be soldered. To achieve the highest strength, the choice of designs for connecting jewelry parts when soldering is of great importance. 58

Soldering control. Solder joint defects. Important aspects are solder control and solder joint defects, as these can lead to weakening and failure of the joint. The main defects include low weld strength, slag inclusions, solder sagging and sagging, weld porosity, cracks in the welds, burn-through and melting of the base metal, as well as displacement and distortions in solder joints. The low strength of the seam is due to poor wetting and flow of solder on the metal surface, which occurs due to insufficient cleaning of the soldering area from oil, oxide film and other contaminants, as well as due to weak activity and insufficient amount of flux, and insufficient heating of the surface of the product. As a result, the seam is weak. Poor wetting is due to the solder rolling into a ball rather than spreading. The occurrence of poor solder flow into the gaps between the parts is due to distortions in the connection and too large a gap between the soldered parts. As a result, the solder does not fill the gap completely, resulting in an incomplete seam. The appearance of slag inclusions in the solder joint occurs when the melting point of the flux is higher than the melting point of the solder, and when the specific gravity of the flux is greater than the specific gravity of the solder. In such cases, the flux cannot be forced out of the gap, and this makes the weld weak. The presence of residual flux also degrades the quality of the weld. Seam porosity, caused by insufficient amount of solder, high heating temperature and evaporation of the solder and flux components during the soldering process, is the cause of a decrease in the quality of the seam and the strength of the solder joint. Cracks in the seam can occur due to the displacement of parts during the solidification of the solder or the sharp cooling of the seam after soldering. Insufficient heating of the surfaces to be soldered leads to the formation of solder runs and sags, which also affect the quality of the seam. High heating temperature and prolonged heating of the soldered product can lead to burn-through and melting of the base metal. Careful quality control of work at all operations of the soldering process is necessary, since the absence or poor fastening of parts with fixing steel wire before soldering can lead to misalignment and distortions in solder joints. In addition, soldering defects weaken joints and disrupt the jewelry manufacturing process. Checking the quality of the mount and fastening of jewelry parts is a key step in making a quality solder connection. For this purpose, you can use an external examination, an optical magnifier or a microscope. Equally important is the control of the use of materials and devices in preparatory operations. Polishing. Polishing is the most important operation that gives the final look to the jewelry and plays an important role in its creation. The polishing process achieves a mirror-smooth surface, which is an essential part of jewelry making. There are various ways of polishing, including manual and mechanized. Hand polishing is usually done using special tools such as wooden sticks that are stretched with threads. But no matter what methods jewelers use, polishing is always of paramount importance. It not only improves the appearance of the product, but also enhances all other operations carried out in the process of creating a piece of jewelry. Thanks to polishing, the jewelry acquires a high luster and attractiveness, which makes it even more valuable and desirable for buyers. 59

Hand polishing is a traditional and masterful way to achieve a perfect surface. This requires certain skills and craftsmanship, as jewelers must be precise and accurate when working with the details of the product. They use various tools and fixtures to achieve the desired result. However, with the development of technology and the advent of new materials, mechanized polishing is becoming more and more popular. Machines and special devices allow jewelers to achieve high precision and polishing speed. This saves time and effort, which is an important factor in today's jewelry industry. Therefore, polishing is an essential part of the jewelry making process. It gives products shine and attractiveness, makes them more valuable and desirable for buyers. Through manual and mechanized polishing, jewelers can achieve the perfect surface that enhances the beauty and uniqueness of each piece. For polishing small holes, chain links and larger holes, linen or cotton threads can be used with a polishing paste applied to them. To polish small holes, you can weave a bunch of threads in the form of a braid. The procedure for polishing with threads is as follows: first, the thread is fixed on a hanging hook. The workpiece is then pulled through the thread or bundle and pulled tight. After that, a polishing paste is applied to the thread. Further, with the help of a stretched thread or bundle, the object is held back and forth until it is completely polished from the inside. It is important to monitor the condition of the thread or bundle during operation so that they do not break or loosen, which can lead to a decrease in polishing efficiency. In order to ensure reliability and aesthetic appeal, it is necessary that the bundle does not sag, and the edges of the hole are rounded even with low tension. To achieve this effect, various methods of surface treatment of the jewelry can be used.

One such method is polishing flat surfaces with a leather polishing file. This device can be made independently. Take a piece of a wooden ruler and cover it with soft leather. Then apply polishing paste to this surface. Thus, you will have a handy tool for polishing your jewelry. A leather polishing file is especially useful when finishing the surface after sanding and polishing with a steel or agate iron. With it, you can achieve a final mirror shine and give the product a sparkling look. This method allows you to achieve a perfect finish, which is especially important for creating high-quality jewelry. Mechanized polishing is a technological operation that is performed on a polishing machine or using a drill. For this procedure, various tools are used, such as elastic circles, hair brushes and cotton fabric circles. To ensure the effectiveness of polishing, a polishing paste is applied to the surface of these wheels and brushes, which contains abrasive powders of various grain sizes. The choice of paste depends on the stage of polishing - initial or final. In addition, polishing pastes also contain fine abrasive powders, which help to achieve the perfect gloss and smoothness of the surface of the products. Mechanized polishing is an integral part of the production process in various industries such as jewellery, the automotive industry and the medical industry. It allows you to achieve high precision and quality of surface finish, as well as remove defects, including scratches, stains and bumps. The use of polishing machines and drills reduces labor costs and increases the productivity of the polishing process. This is especially important when working with large volumes of 60

products or when it is necessary to process hard-to-reach places. Also, mechanized polishing allows you to achieve a uniform finish on the entire surface of the product. It is important to note that the correct choice of polishing paste and tools is a key factor in achieving the desired result. Professionals must consider material, surface type, and finish requirements when selecting tools and paste. Proper polishing technique is also essential to avoid surface damage and to obtain optimum polishing quality. In conclusion, mechanized polishing is an efficient and reliable method for achieving high surface finishes. Technological progress and the development of new materials and tools continue to improve this process, making it more accurate, faster and more accessible to various industries. Jewelry polishing is a process that involves the use of various materials and additives. To achieve the perfect gloss and smoothness of the surface, special pastes containing various binders and abrasive materials are used. Chromium oxide, crocus (iron oxide) and silica are just some of the abrasive materials that are used in polishing. To create a paste, binders such as stearin, paraffin, tallow, caeserin and wax are used in combination with abrasives. These ligaments provide not only the adhesion of the paste to the surface, but also help to achieve a certain level of smoothness and shine. In addition to binders, special substances are added to the pastes, such as bicarbonate of soda and oleic acid. These additives help improve the polishing process, making it more efficient and effective. After polishing is completed, the piece of jewelry must be thoroughly cleaned of all polishing residues. To do this, it is placed in a cleaning solution, which helps to remove all traces of the paste. The product is then washed in an ultrasonic cleaner to remove any remaining dirt, and finally rinsed with clean water and dried with a soft cloth or dryer. Thus, the process of polishing jewelry requires the use of various materials and additives, as well as thorough cleaning, in order to achieve the desired result - perfect shine and smoothness. Flannel wipes perfectly absorb liquid and perfectly clean surfaces from dust and dirt. In addition, they are soft to the touch and do not leave scratches on surfaces. Flannel is a natural fabric obtained from cotton fibers, which has high strength and durability. Flannel wipes can also be used to polish glass and metal surfaces, they leave no streaks and add shine.

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VII. Mechanisms used in jewelry The mechanisms used for grinding and polishing belong to a separate group of metal cutting methods. Grinding serves mainly to give parts a smooth surface. Polishing provides a strong metallic sheen (gloss) on a smooth matte surface. The holes of each pobedit insert have certain diameters, which allows it to be used for manually pulling tubes and wire into smaller diameters. The purpose of these operations is not to give the metal a certain shape, but to give the finished products a certain surface finish. Grinding and polishing are similar to each other, and it is impossible to draw a clear line between them. Now the most common grinding and polishing machines for these operations. Tumbling or vibrating are mass polishing and grinding methods, and drums and containers are used for this. A polishing agent is loaded into the drum along with products, which are polished steel balls with a diameter of 1.5 to 5.0 mm. The mass of the balls is two parts by weight of the products. For mechanical polishing, a two-spindle polishing machine is used, equipped with nozzles for polishing tools - elastic circles. Varieties of circles include felt, hair, cloth and thread (fluff), which differ in material, shape and purpose. Polishing pastes are applied to the surface of each circle. The optimal rotation of the machine is 70 rpm, and the duration of the process can be up to three hours, depending on the condition of the surface. Mechanical abrasive polishing is carried out using elastic wheels and brushes with abrasive pastes, and in some cases polishing is done manually using a crowbar. For initial polishing, felt wheels are used, which should hold abrasive pastes well on the surface and be durable in use. Hair circles, which have elasticity, are used for polishing products of complex design with an openwork or relief surface. For final polishing and shine, cloth wheels are used, which are discs made of material collected in bags. Materials such as calico, calico and flannel can be used as material for these circles. For drilling and milling, which are additional operations for creating recesses or holes of a cylindrical shape in the workpiece, hand-held mechanical drills and electric drills (drill) are used. To achieve the same goals, thread circles can be used, on the surface of which polishing (abrasive pastes) are applied with a selected grain size, depending on the stage of polishing. Abrasive materials for pastes are chromium oxide, crocus (iron oxide) and corundum micropowders. Mounting operations in jewelry include the use of a drill, which can be used not only for drilling, but also for milling. Milling allows you to process flat or convex surfaces that are impossible or difficult to file, depending on the shape of the cutter. In jewelry making, various types of cutters are most often used, such as conical, cylindrical end, combination, ball, cavity and special cutters. Another tool used in jewelry is a scriber - a rod with a pointed end that is used in marking operations. A center punch is a large steel rod with a pointed working end that is hardened. It is used for making recesses for drilling. The working end is steel and must be hardened. Marking compass is a steel compass in which the working ends are sharpened to form a cutting angle. Calipers - necessary for measuring external and internal dimensions, depth of holes and protrusions. Its division value is 0.1 mm. The marking plate is a flat steel sheet measuring 150x150x2 mm. It is used for drawing marks on the metal surface to be marked. 1. Flahaizens - steel (hardened) dressing slabs, which are flat, grooved and other shapes and profiles. 2. Shperak - dressing tool in the form of a small anvil with a flat and round working part. 62

3. Crossbar - a steel conical rod with a working part and a handle. The working part has the form of a truncated cone, 200-250 mm long, with a small diameter of 10-15 mm and a large diameter of 20-24 mm. The length of the handle is 20-100mm and the diameter is 20-25mm. 4. Metal ruler designed for straightening and bending. 5. The surface of the ruler is rough. For cutting sheet metal use: 1. Steel scissors with a small working part and long handles. 2. Jewelry scissors are designed for cutting solder. 3. There are various types of pliers: pliers with flat working jaws, round-nose pliers with round-conical jaws, tire pliers, flat-pointed pliers, grooved, "beaks" and others. 4. Hammers can be metal weighing 50 g and 100 g, as well as textolite of different sizes. 5. Anka and pumzel are used to give the workpiece a spherical shape. 6. Jigsaw - a small knife-like machine that is used for cutting openwork and individual parts of the product. Jigsaw blades are a hardened steel strip of rectangular section, on which teeth are cut. The size of the teeth on the blade depends on the size of the cross section of the file. The working parts of the scissors must be well sharpened and fit snugly together. Nippers are needed for biting off small parts. Universal equipment - a drill that allows you to mechanize the processing of jewelry, is used for drilling, filing and grinding products. Cutters for filing - burs, consist of a tip (of different sizes, profiles and notches) and a shank, mounted in a drill with collet clamps. Drills - rods made of steel, consist of a shank and a working part, types of drills - feather, spiral, center, are used for drilling holes. A scraper is a steel rod 100-120 mm long with a three-sided sharpening at the end. Ribs formed by trihedral conical sharpening make up the working part. The scraper sharpening angle formed by the edges depends on its cross section and purpose. It is used to cut thin metal surfaces. Files are filing tools, consisting of a working part and a shank, made of tool steel. They vary in size, profile and notch. The profile can be trihedral, semicircular, round, flat, rhombic, differently convex, square and others. Most jewelry files are 200 to 270mm in size and have a sharp nose. The size of the tooth decreases as the number increases. The wooden handle is mounted on the shank. Needle files have a smaller cross-sectional area compared to files. Their sizes are 140 and 200mm. Depending on the profile, they can be trihedral, wedge-shaped, rhombic, flat, square, semicircular, convex, grooved, oval or round. The notch is 0-6. The working part has a length of 70-80mm with a total length of 140mm and 95-100mm with a total length of 200mm. The length of the working part of the needle files is 40 mm, with a total length of 140 mm. They differ from ordinary needle files in the shape of the shank. Hand vises come in wood and metal. Wooden vices can be screw or wedge-shaped. They are used to fix the product during filing and other work. You can use a soldering iron for soldering. Also an important tool is letkal - a wooden plate with asbestos coating or cardboard, which serves as a lining for soldered products. For the convenience of working with soldering, ordinary and clamping tweezers of different sizes are used. An aqueous solution of the components in a 1:1 ratio by volume is considered the most universal flux, consisting of a solution of borax and boric acid. A saturated solution of borax is 63

sometimes used as a flux in certain situations. The flux ensures the safety of the soldered parts, protecting them from oxidation. Stichels are steel cutters with a wooden handle used for setting stones. Stiheli are made of steel grades U12A or HVG with obligatory hardening. The blade of the engraver has a length of 100-120 mm, and the handle has a mushroom shape. The upper part of the chisel blade is called the back, and the lower part is called the blade. Well-polished blades and burr walls require cutting edges. Sharpening is carried out on fine-grained bars lubricated with machine oil. Polishing is carried out on marble bars and leather, which is covered with polishing paste.

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VIII. Jewelry production technologies. Basic moments. Jewelry is an integral part of the culture and art of the East. They are distinguished by their beauty and splendor, attracting attention with their unique colors and materials. Jewelry copywriters understand that the colors of precious and semi-precious stones, as well as hot enamel, play an important role in creating unique jewelry. Oriental jewelry is known for its variety of colors. Carnelian, coral, turquoise, lapis lazuli and amber, as well as ruby and emerald, are just some of the most popular stones used in beads, rings, bracelets, earrings and pendants. Oriental masters prefer to use two primary colors - red and blue, which are predominant in the art of the Middle East. Red, represented by ruby, coral and carnelian, has a protective meaning and symbolizes life, passion and activity. It attracts attention and gives the decoration an energetic and powerful look. The blue color represented by lapis lazuli and turquoise symbolizes the sky and water. This color gives the decoration a sense of calm and harmony, as well as natural beauty. The Berber decorations of the Maghreb also use blue-blue enamel to emphasize the connection with the sky and water. In addition to red and blue, other colors are widely used in the design of oriental jewelry. Green, represented by emerald, jade and enamel, is associated with fertility and the life-giving light of the sun. This color scheme is very popular in Berber enamel jewelry. Yellow, represented by amber, enamel and mastic, is also associated with sunlight and fertility. To create unique jewelry, oriental craftsmen also use black and white colors, represented by agate. These colors symbolize power and purity, and add elegance and sophistication to the design. It is important to note that oriental jewelry not only surprises with its colors, but also embodies deep symbolic meanings. Round pendants, for example, are reminiscent of the solar cult and symbolize wealth and prosperity. Rings with seals indicate the special status of their owner. Images of animal and plant ornaments are associated with fertility and symbols of the Family, Upper and Lower worlds. All these elements reflect ancient beliefs and traditions that continue to live in the art of oriental jewelers. In conclusion, jewelry decorating is an art that requires fine taste and a deep understanding of the symbolic significance of colors and shapes. Oriental craftsmen master this art, creating unique and delightful jewelry that attracts attention with its beauty and elegance. Protective Symbolism of the East in Jewelry Art. The mysterious and attractive symbolism of the East has always left an imprint in art and culture. One of the most important and protective amulets worn from generation to generation is the symbol of the eye. Dating back to ancient Egypt, this amulet has infiltrated a variety of cultures and has become an integral part of Middle Eastern arts and crafts. In the Arab world, it is known as "ayn al-hasad", which has the power to protect against the evil eye. In Turkey, the amulet received the name “nazar bonjuk 15” and became a popular souvenir for tourists, protecting its owners from the effects of the evil eye and negative energy. Besides the eye, another prominent symbol of protection in Middle Eastern art is the "hamsa", also known as the "hand of Fatima". This amulet depicts a palm with five fingers, which symbolizes the number five in Arabic. Sometimes you can see a blue bead on the palm, adding an additional layer of protection to the amulet. This motif is widely used in both Muslim and Jewish arts and crafts, uniting different cultural practices in a common symbolism of protection and well-being.

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Nazar Bonjuk is a Turkish amulet against the “evil eye”. It is believed to bring good luck.

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Jewelry created by craftsmen from the Middle East and Central Asia carries a wealth of animal motifs. Animal images, stylized to varying degrees, are a characteristic design element for both nomadic and sedentary peoples in these regions. The roots of this tradition go back to pre-Islamic animalistic cults, which were embodied in unique jewelry. For example, in Egypt, until recently, amulets with the image of a scorpion were popular, designed to protect against the bites of this dangerous insect. Animal symbolism is also reflected in ancient Egyptian amulets in the form of a scarab - a symbol of eternity and rebirth. In the jewelry of the tribes of Central Asia and Afghanistan, images of birds and fish stand out especially. These motifs carry deep symbolism - birds rising to the sky can be interpreted as a desire to rise above everyday worries, and fish floating freely in the water symbolize a connection with emotions and intuition. Thus, the symbolism of the eye, palm and animals has become an integral part of the jewelry art of the Middle East and Central Asia. These amulets and motifs are not only beautiful decorations, but also convey the rich heritage and cultural depth of this region, serving as protection and inspiration for their owners. Images of birds in the decorative and applied arts of Central Asia and the Middle East have ancient roots. In primitive societies, people attached special importance to birds, viewing them as symbolic representatives of their ancestors and totems that warned them and brought protection. Over time, these birds became objects of divine worship, and then the image of a female bird appeared. The image of birds, whether in full form or individual parts of them, continued to serve as symbols of various aspects of life. They were associated with well-being, fertility, wealth, family happiness, fate and the spiritual sphere. The power and rule of the rulers were also often associated with the symbolism of birds, and they considered them to be their patrons. Birds took on a sacred meaning and were associated with "solar" deities, symbolizing the idea of fertility and abundance. In Central Asia, especially during the period of Muslim influence, feathers and claws of birds were used to decorate women's forehead and temple jewelry and gave them magical properties. In the art of Central Asia, the bird was also associated with the image of the mother goddess and the ancient pre-Muslim deity Ishtar. In the Iranian-Turkic cultures, throughout ancient times, the symbol of a bird-woman, known as Umai or Humayun, was widespread. Images of birds on jewelry can be traced back to the Bronze Age in the territory of ancient Khorezm, where they are regularly found in archaeological excavations from the 4th-3rd century BC. This sacred image of birds was also preserved and developed in the arts and crafts of Central Asia in the 19th and 20th centuries, remaining an important element of culture. In addition to images of birds, fish also have a special meaning in decorative ornaments. It symbolizes fertility and is widely used in jewelry from the Mediterranean region of the Middle East, such as Syria, Libya, Morocco and Egypt. This fish symbol in jewelry design has its roots in ancient Greco-Roman times. Mention should also be made of the widespread popularity of the symbolism of celestial bodies, in particular the Sun, Moon and stars, in the art of the Middle East. These images on jewelry can be traced back to ancient times and have a benevolent meaning. The symbols of the Sun, Moon and stars are used as amulets designed to protect the owners of jewelry from adverse circumstances and events. In addition, the image of the crescent also has a special meaning in the art and culture of the Middle East. This symbol is often associated with Islamic symbols and plays an important role in the religious and ritual practices of this region. It should be noted that the arts and crafts of Central Asia and the Middle East embody a rich cultural heritage and a wealth of symbolism that permeates every element of jewelry and its design. These symbols not only reflect ancient 66

traditions and beliefs, but continue to be important in the modern era, testifying to the deep connection between the art, culture and spiritual values of this region. The world of precious metals and stones in the Middle East and Central Asia is permeated with unique symbols and styles. Despite common features, each ethnic region has its own unique style. For example, the Berber jewelry of North Africa amaze with its large size and symmetrical geometric patterns. The tribal jewelry of the East of the High Atlas is embodied in massive products with a complex shape, made using the techniques of chasing and inlay. Treasures of Yemen Yemeni silver jewelry is a true work of art, almost architectural in its beauty. The filigree and grained finishes give them a unique charm. These are jewelry created by craftsmen from the Jewish communities of Yemen, who passed on the secrets of jewelry craftsmanship from generation to generation, enriching the traditions and techniques of the arts and crafts of the Middle East. Jewelry of Central Asia and Afghanistan Symbolism and beliefs are closely intertwined in the jewelry of this region. The nomadic and sedentary peoples of Central Asia and Afghanistan believed in the power of protective amulets, and these beliefs are still reflected in the design of jewelry. These products not only decorate, but also protect their wearers. Uzbek Symbolism the Fergana Valley in Uzbekistan is rich in decorations in which echoes of Zoroastrian symbolism can be seen. Particularly impressive is the “bodom oy” forehead decoration, which is associated with the symbolism of the Zoroastrian goddess of water Anahita. Jewelry from the Middle East and Central Asia are real treasures of cultural traditions. They not only decorate their bearers, but also tell us about the richness and diversity of the history of this region. Each item is a unique work of art that takes us into the world of ancient symbols, beliefs and skills of craftsmen whose talent lives on in every jewel. Fundamentals and technologies of jewelry production Jewelry casting is one of the legacies of Ancient Egypt, and it is currently actively used by modern craftsmen using advanced equipment. However, the manufacturing process has not changed much since the time of the pharaohs. Before the stone is set into the product, the workpiece is ground and polished. Grinding and is carried out to level the profile, and polishing gives the product a shine. An interesting method is tumbling, which combines grinding and polishing. In this case, the products are placed in a drum with abrasive material, the composition of which may vary. Although the quality of the product using this method may be slightly lower than when using separate grinding and polishing, tumbling is a quick and affordable technique. However, modern technologies in jewelry casting are not limited to grinding and polishing. Today, craftsmen use innovative high-precision equipment such as computer modeling and 3D printing. These techniques allow you to create complex and unique designs that were not possible before. Computer modeling allows craftsmen to visualize a product before it is created, which helps them accurately determine its shape and details. 3D printing allows you to create accurate models of products from various materials, including metals and resins. Another interesting feature of modern jewelry casting is the use of special wax models. Craftsmen create parts from wax, which are then used to create metal castings. This method allows you to create complex and detailed jewelry with a high degree of precision. In addition, modern technology allows craftsmen to experiment with different materials and finishes. For example, the use of rhodium plating creates jewelery with a brilliant silvery hue, while rose gold or platinum plating creates a luxurious look. Also, modern craftsmen can use various precious and semi-precious stones to add extra shine and beauty to jewelry. As a 67

result, although jewelry casting retains its roots in history, modern technology and innovation allow craftsmen to create unique and high-quality pieces. Through the use of advanced equipment, computer modeling, 3D printing and other techniques, jewelers can bring the most daring ideas to life and create real works of art. Casting using inexpensive stones is one of the most popular techniques used in creating silver and gold jewelry. However, it is worth noting that not all models are suitable for this process. The insertion of stones is carried out directly into the wax models during the formation of the jewelry. After firing in the mulled stone, the stones remain inside and are securely fixed after pouring with metal. Then the product is sent to the tumbling drum and is considered ready. Although the scrap rate can be quite high when using this technique, production is still considered as economical as possible. One of the reasons for such cheapness is the use of inexpensive stones. Instead of gemstones such as diamonds or emeralds, semi-precious stones such as amethysts, topazes or citrines can be used. These stones have a more affordable cost, which reduces the overall price of the product. In addition, casting using inexpensive stones allows you to create more diverse and affordable jewelry. Instead of being limited to just gemstones, designers can experiment with different colors and shapes of semi-precious stones16. This opens up new possibilities for creating unique and stylish jewelry that is available to a wide range of customers. It is also worth noting that the use of inexpensive stones does not mean that the quality of the product will be low. In fact, modern technology makes it possible to create high-quality jewelry using various stones. Stones can be carefully selected and processed to ensure their beauty and durability. Thus, casting using inexpensive stones is an effective and affordable technique for creating jewelry. It allows you to save on the cost of materials, while providing the opportunity to create unique and stylish jewelry for a wide audience. In the process of manufacturing products using stones, it is necessary to carry out the setting procedure. This important step is the responsibility of the bartack, who sets the stones into the grooves and seals them to prevent them from falling out. However, it often happens that some stones are very brittle and cannot withstand the stress of the setting process, which can lead to chipping. If we are talking about inexpensive cubic zirkonia, then this is not a big problem. However, when using diamonds, such nuances are unacceptable, since these are precious stones of high value. Traditional handmade jewelry making is still popular, but modern automated processes are becoming more and more popular. The quality of each manufacturing step plays an important role in determining the overall quality of the finished product. The more carefully and efficiently each stage is performed, the higher the cost of the final product will be. But more interestingly, process automation in the jewelry industry not only improves the quality of products, but also ensures more efficient use of time and resources. Automatic systems allow precise control of every step of production, minimizing the possibility of errors and increasing productivity. Moreover, modern technology allows you to create complex and unique designs that were previously not possible manually. Automated systems provide accuracy and repeatability, which is especially important when creating serial products. So while manual manufacturing still has its place in the jewelry industry, automated processes are becoming more and more in demand. They allow not only to improve the quality and uniqueness of products, but also to improve production efficiency.

16

Semi-precious stones (also known as gemstones) are portions of minerals that, in refined and cut form, are used to create jewelry or other embellishments.

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From sketch to final product When an artist starts work on a new project, he first creates a sketch on paper. At this point, his idea begins to take on real contours, becoming more concrete and understandable. The designer then takes on the task of designing multiple versions of the same piece of jewelry. Each version may have its own characteristics in the form of design elements, various inserts, fastener options and other details. This process of developing multiple options allows the designer to explore different possibilities and experiment with different ideas. Each version of the decoration is a kind of experiment that helps to identify the most attractive and functional solutions. After all versions of the product are ready, it is time to choose the best one. The designer analyzes each version in terms of aesthetics and functionality. He pays attention to how each detail fits into the overall style and visual impression, as well as how convenient and practical the decoration is to use. Of all the submitted versions, the one that best meets the specified criteria is selected. It can be the piece with the most attractive design, the most comfortable clasp, or the most interesting inserts. It is important to find a balance between aesthetics and functionality so that the decoration is not only beautiful, but also practical to use. Sketching and developing multiple versions allows the designer to explore different ideas and choose the best one. This process is an important part of the creative process and helps create a unique and eye-catching piece of jewelry. In the jewelry industry, before starting the casting process, the caster must prepare the alloy that will be used for pouring. Depending on the required metal (in our case, silver), the caster mixes it with a master alloy - a mixture of other metals such as copper, nickel, zinc, and possibly others. These components are then melted together and thoroughly mixed to ensure an even content. After that, the molten mixture is poured into a pre-prepared plaster mold. It cools down, and then the plaster mold is broken to remove the finished product in the form of a Christmas tree from metal. The remains of gypsum are washed off with a jet of water, and the Christmas tree is taken out for further processing. Further, cast wax Christmas trees are disassembled into individual elements, the products are detached and sent for processing. And the remaining rod, which contains sprues - metal rods to which the products were attached, is sent for remelting. Remelting is a process in which the core and gates are subjected to high temperatures to melt the metal and separate it from the gates. After cooling and solidifying, the resulting metal can be reused to create new products. The casting process in jewelry production includes not only pouring the alloy into a plaster mold, but also subsequent processing and melting of the remains. This allows you to make the most efficient use of materials and create high-quality jewelry. Tumbling and mounting are two important steps in the processing of various products. Tumbling is a polishing method that is carried out by mixing products in a special drum with abrasive materials, such as ceramic particles in the form of needles, balls or pyramids. This process allows you to achieve a smoother and denser surface of jewelry. However, tumbling is not the only stage in the processing of products. After tumbling, mounting may follow, which includes various operations for assembling and fixing the components of the product. For example, in jewelry making, mounting may involve setting gemstones into settings or attaching clasps to bracelets. These processing methods are essential for creating quality products. Tumbling helps to achieve the perfect surface, removing irregularities and defects, as well as giving the product a more attractive appearance. Mounting, in turn, guarantees the reliability and durability of the product, ensuring the correct fastening of all its components. In addition, various techniques and tools can be used in the process of tumbling and mounting. For example, vibratory drums or centrifugal machines can be used for tumbling, and special tweezers, adhesives and other tools can be used for mounting. 69

It is important to note that these methods are not limited to jewelry production. They are also widely used in other industries such as watches, optics, electronics, etc. Each industry may have its own specific methods and technologies, but the overall goal remains the same - to create high-quality and attractive products. In addition, tumbling and mounting are important steps in the processing of products that allow you to achieve the perfect surface and guarantee the reliability and durability of the product. Using various techniques and tools, manufacturers can create high-quality and attractive products in various industries. In jewelry production, most of the products require careful manual processing. This includes assembling, finishing and fitting parts that require a high degree of care and skill. The quality of the mount has a direct impact on the strength and durability of the future piece of jewelry. When the components of the piece of jewelry are assembled, the polishing process begins, which is also done by hand. Skilled craftsmen carefully work the surface of the product using various techniques and tools to achieve the perfect gloss and finish. It is important to note that manual processing is an essential part of the jewelry making process. All this takes time, patience and skill to achieve a high level of quality. Each product is unique and requires an individual approach to its creation. In addition, in the process of refining and fitting parts, the craftsmen can make some improvements or adjustments to meet the specific requirements of the client. This may include changes in the design, size or appearance of the product. The process of creating jewelry requires not only the use of specialized tools and technologies, but also direct human intervention and skill. Hand processing and polishing give each product individuality and uniqueness, making it a real work of art. This explains why jewelry created using such methods is valued and sought after all over the world. Rhodium is one of the rarest platinum group metals. Its high strength, resistance to high temperatures and aggressive environments make it ideal for use in silver and white gold jewelry. But rhodium not only provides protection against tarnishing and scratches, but also has hypoallergenic properties, making it safe for people with sensitive skin. Electroplated rhodium plating allows a thin coating of rhodium to be applied to the surface of the item, creating a protective barrier that prevents oxidation and retains the shine for a long time. In addition, rhodium has antibacterial properties, which makes it especially valuable for jewelry that comes into direct contact with the skin. Galvanic rhodium plating not only ensures the durability and beauty of products, but also preserves their original quality. This means that even after the rhodium process, the hallmark of the product remains unchanged, which is an important factor when choosing jewelry. In addition to its use in jewelry, rhodium also finds use in other industries. For example, its high temperature resistance makes it an ideal material for catalysts in the automotive industry. Rhodium is also used in the manufacture of electronics, optics, and even some medical devices. Thus, rhodium is not only a rare and valuable metal, but also a multi-purpose material with unique properties. Its use in jewelry provides not only beauty and durability, but also safety for those who wear the jewelry. Setting stones is the final step in the production of jewelry. It includes the selection of stones that will be used for each particular product. Two main methods can be used in the bartacking process: glue or metal bartacking. Regardless of the method chosen, at this stage, accuracy and precision of work are especially important.

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The jeweler must skillfully install the stones into the grooves so that they are securely fixed and do not fall out while wearing the item. Working with rocks can be especially challenging due to various factors. For example, amber, which is widely used in jewelry, is of organic origin and is distinguished by its softness. This means that the jeweler has to be more careful with this material to avoid damage. In addition, amber often contains inclusions and air bubbles, which makes the process of working with it even more laborious. A jeweler who specializes in working with amber must have a thorough knowledge of the physical properties of this stone. He must know what level of softness amber has and how it reacts to various influences. This is the only way to avoid chips, cracks or other damage during the bartacking process. In addition to amber, there are other stones that can be difficult to set. For example, opals often have internal cracks that can widen if processed incorrectly. Emeralds, on the other hand, can be very fragile and require extra care when setting. As a result, setting stones is an art that requires skill and experience. Jewelers have to take into account various factors to ensure that the stones are securely set and not damaged over time.

Necklace made of silver, coins and multi-colored stones This stage of jewelry production plays an important role in creating high-quality and durable jewelry that will delight its owners for many years. Creating a complete and self-sufficient jewelry collection is a complex and multi-stage process in which each stage is closely related to the other. One of the key stages is modeling, since the simplicity and speed of order production directly depend on it. Usually, the preparatory stages take about a month, as well as the direct implementation of the order in production. 71

Among all types of jewelry, the production of earrings is considered the most expensive. When calculating the retail price, it is necessary to take into account the cost of producing two products, which makes this process complicated. Also one of the challenging aspects is the creation of rings, not only in terms of production (requires a separate master model and elastic band for each size), but also taking into account the demand for different sizes. When ordering, it is necessary to take into account the popularity of certain ring sizes. However, it is worth noting that the above process only applies to the creation of solid pieces of jewelry such as rings, bracelets, pendants and earrings. Other jewelry elements, such as chains and clasps, are usually purchased from specialized companies that produce them. This allows you to focus on the main elements of products and speed up the production process. Of course, the described production model is not the only one, but it is considered the most suitable for industrial scale. Each jewelry company may have its own characteristics and approaches to production, however, the basic principles remain applicable.

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IX. Filigree or the technique of the finest patterns Filigree, also known as filigree, is a wire pattern that can be openworked or soldered to metal. In addition, spoons and coasters, which are often used in buffets of respected families, can be made in filigree. The word "filigree" itself reflects the process of its manufacture: The Latin word "filum" means "thread", and "granum" - "grain". In Russian, the word "filigree" comes from the old Russian word "skat", which means "twisting"17. Filigree is most often made from silver, but designs from gold and other metals can also be found. Silver and gold are very soft metals, which makes them easy to draw into thin wires. The wire used to create a scanned pattern can be smooth or twisted in the form of ropes and spirals. Filigree was known throughout the ancient world, including Crete, Egypt, Troy and Greece from the 6th to 4th centuries BC. This technique is one of the main and "original" in jewelry art. Filigree can create amazingly beautiful and complex patterns that decorate various objects, from jewelry to home decoration. It is interesting to note that filigree has its own characteristics in different cultures. For example, in Arabic and Indian art, filigree is often used to create jewelry such as earrings, rings, and necklaces. In Chinese culture, filigree is used to make traditional items such as teaspoons and brush coasters. In addition, filigree can be used to decorate items of religious significance such as icons and amulets. Today, filigree remains a popular art valued for its uniqueness and craftsmanship. Many jewelers and artists continue to use this technique to create amazing jewelry and art. Thanks to filigree patterns, objects acquire an exquisite and graceful look, attracting admiration and admiration for their beauty and subtlety of execution. Filigree is the art of creating jewelry from fine wire or grains of metal. There are different types of filigree, each with its own characteristics. Brazed filigree is a technique in which wires and grains are soldered directly onto sheet metal. This creates a unique raised effect, adding dimension and texture to the decoration. If the background remains unchanged, then such filigree is called background or “blank”. It can be used to create intricate patterns and details on the surface of a piece of jewelry. In perforated or sawn filigree, after soldering, the background is removed by punching or sawing. This allows for more open and airy patterns where the wire forms fine weaves and details without being limited to sheet metal. Such jewelry has exquisite beauty and attractiveness. Another variant of filigree is openwork filigree. In this technique, the wire is bent and twisted in such a way as to create an open, airy structure. Jewelry in the style of openwork filigree look elegant and delicate, their transparency and lightness create a feeling of weightlessness. Filigree is an ancient art that has been popular across cultures and eras. It requires meticulous work and craftsmanship to create unique and beautiful jewelry. Today, filigree remains a popular and sought-after type of jewelry art, attracting attention with its sophistication and uniqueness. 3D filigree is a unique art that involves the creation of elegant and complex metalwork. It comes in a variety of shapes and can be used to create a variety of objects, including cups, vases, trays, caskets and even images of animals and birds. The process of creating filigree is very laborious and requires skill. First, the master creates individual parts from metal, which are then joined together to form a single composition. This can be either flat filigree, used in jewelry, or

17

Twisting (American pronunciation - ˈtwɪstɪŋ) is a noun in English that means “twisting”, “warping of boards when drying”, “spinning”, “twisting”.

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volumetric filigree, creating three-dimensional shapes. In jewelry, filigree can be used to create various items such as pendants, brooches, rings and bracelets. Frame pendants, for example, can be decorated with flat filigree, while hemispherical complex brooches and rings can be created using openwork-volumetric filigree. But filigree is not limited to jewelry. It can also be used to create sculptural elements such as small animals, birds or bells. These elegant and detailed figurines make wonderful home decorations or gifts. Filigree can be made from a variety of metals, but one of the most popular materials is silver. Its brilliance and strength make it ideal for creating delicate and durable filigree pieces. However, in addition to silver, filigree can also be made from other metals such as gold, platinum or even copper.

Thus, filigree is an art that combines craftsmanship and creativity. Its graceful and complex shapes make each piece unique and beautiful. Whether it is jewelry or sculptural elements, filigree always attracts attention with its beauty and grace.

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Melting of bronzes and brasses is carried out as follows: first, dry fine charcoal is poured into the bottom of the crucible to cover the liquid metal. Then red copper is loaded and melted, and deoxidation is carried out with phosphorous copper in an amount of 0.2-0.3% of the charge weight. After that, ligatures are loaded, including copper - nickel for copper-nickel alloys, such as cupronickel and nickel silver. After melting the ligatures, zinc, tin and lead are introduced. Then the metal is mixed with a metal or graphite stirrer, heated to the required temperature and cleaned of slag and charcoal. Then, secondary deoxidation is carried out with phosphorous copper in the amount of 0.1-0.2% by weight of the charge and the finished product is released. For melting some bronzes and brasses, it is necessary to use special fluxes, which not only protect the metal from oxidation, but also form slagging from various oxides. When melting aluminum bronzes, various fluxes are used, such as glass, soda, borax, or a mixture of common salt (75%) and fluorspar (25%). The flux is added in an amount of 1-2% of the total weight of the raw material after loading. The melting point is 1080-1220 °C, depending on the composition of the bronze. When melting brass, the amount of phosphorous copper for deoxidation is reduced to 0.10.2%, since zinc also has the ability to deoxidize. The introduction of aluminum into brass before zinc is carried out to prevent the evaporation of zinc, since the Al2O3 film formed on the surface of the melt will interfere with this process. To prevent strong cooling of the metal, zinc is introduced heated to 150-250 °C. The release temperature of brasses varies depending on their composition and is 1000-1100 °C. Aluminum alloys are rarely used in artistic casting. However, they are used in jewelry casting, as well as for the manufacture of interior decorations and aluminum products that are anodized. To maintain the furnace, it is important to have several replacement crucibles for each group of alloys. It is especially useful to have different crucibles, including graphite crucibles for non-ferrous alloys. Even with different crucibles, it may be necessary to flush each time you change alloys to clear the crucible of residue from the previous melt that could be detrimental to the next alloy, e.g. when changing from silicon to tin bronzes, etc.

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Casting jewelry castings This is an important process in the production of jewelry made from precious metals such as gold and silver. This method has its own characteristics, which are associated with the characteristics of materials and requirements for products. One of the main features of casting jewelry from precious metals is the scarcity of the metal used. Gold and silver are precious resources and should be spent as efficiently as possible. Therefore, the casting process must be precise and minimally demanding on the material. Another important feature is the need to manufacture small thin-walled and openwork products of complex configuration. Jewelry often has intricate patterns and details that must be reproduced with great precision. This requires specific casting methods and technologies. In addition, the surface of the jewelry must be clean and free from defects. This is especially important for precious metals, as any defect can significantly reduce the value of the item. Therefore, during the casting process, it is necessary to ensure high parameters of surface cleanliness. To solve these problems, special technologies are used in investment casting of gold and silver alloys. In particular, special rubber molds are used, which make it possible to create molds for the manufacture of investment models with high precision. To create the models themselves, synthetic wax-like materials are used, which have the necessary resistance to temperature and can be easily removed after casting. The molding of investment models is carried out using a uniform cristoballite-gypsum filler. Pre-evacuation of this filler helps to avoid possible defects in the casting process. However, one of the most important steps in casting precious metal jewelry is filling the casting cavity with liquid metal. Various methods are used for this, such as the use of centrifugal forces or atmospheric pressure. These methods allow you to fill the mold evenly and create a product with high accuracy. The investment casting method has significantly expanded the range of jewelry made from gold and silver alloys. Thanks to this technology, various designs and shapes that were previously difficult to obtain have become available. Product quality has also improved due to a more precise and efficient manufacturing process. In addition, the labor intensity of manufacturing has decreased, which allows for faster and more efficient production of jewelry. In conclusion, jewelry casting casting is a complex and technical process that has its own unique features and requirements. It plays a key role in the production of high quality precious metal jewelry, allowing you to create unique and beautiful jewelry for different tastes and preferences. The analysis of the investment casting process makes it possible to compare it with other methods such as shell mold casting (SHM) and Estrich casting. It is important to note that when using the Estrich process, the surface of the castings has a high purity and the dimensions are accurate, which eliminates the need for additional processing such as grinding or polishing. This is especially important for jewelry making. The advantage of Estrich casting is that virtually all steps in the process can be done at home. The technology, the necessary equipment and materials make it possible to obtain highquality jewelry castings using simple tools that you can make yourself. This makes the Estrich process accessible to beginner jewelers. To help beginner jewelers-casters, the authors have developed a series of illustrations demonstrating the technological process of casting into single mixtures. These drawings will help visualize each step of the process and make it easier to understand for those who are just getting started in jewelry casting. It is important to note that Estrich casting has other advantages as well. For example, it allows you to create complex shapes and details with a high degree of detail. This is especially 76

useful when creating jewelry with intriguing and unique designs. In addition, the Estrich process ensures uniform filling of the mold, which minimizes the possibility of flaws in castings. However, Estrich casting is an attractive option for jewelers, as it provides high quality castings, process convenience, and the ability to work from home. The illustrations make it easier for budding jewelers to master this technology and create their own unique pieces of jewelry. The traditional process of casting jewelry into single gypsum mixtures, known as the estrich process, involves several steps and operations. One such process is the production of double-sided relief castings using a centrifugal machine. To begin with, to create a fusible model or master model, you need to make a standard or use a small piece of jewelry as a model. Often, 585-carat gold alloy is used as a standard, covering its surface with rhodium. This is necessary because the rubber used to create the mold is vulcanized at elevated temperatures and the process releases small amounts of nitric acid from the rubber. The surface of the standard must be carefully processed and polished to avoid defects on the castings. In addition, the standard should be slightly larger than the finished model (by 56%), due to the shrinkage of the liquid metal when the castings solidify and the need for allowance for machining. This rule is especially important for ornamental casting, where the products are large and require additional machining using metal-cutting equipment. To create a rubber mold, we place the flask with guide pins on a smooth base plate, base down, and fill it with plasticine. Then we press the model standard into the plasticine halfway. We install the second flask on the first flask and pour a solution of gypsum in water. After the gypsum has hardened, we turn over the flasks and remove the plasticine, while the standard remains in the gypsum form. Indentations are made in the plaster, which will later become the guides of the rubber mold. Cut the rubber into pieces and fill the upper half of the mold with them. The flasks are then placed on a vulcanizing press and the pieces of rubber are vulcanized in special shapes. The result is a rubber mold with a double-sided relief that will be used for casting jewelry. After receiving the mold, the next step is to pour the molten metal into the mold on a centrifugal machine. This process produces castings with high precision and detail. The castings then go through several stages of processing, including removal of excess metal, grinding and polishing, to achieve the final look of the piece of jewelry. Therefore, the technological process of casting jewelry into single gypsum mixtures using rubber molds and a centrifugal machine is a complex and multicomponent process that requires precision and professionalism. It allows you to create high-quality jewelry with unique relief and details. The technological process of lost wax casting includes several stages. First, a model and a rubber mold are prepared. The plaster model is broken, the model standard and the rubber halfmold are removed, which are thoroughly cleaned. The mold is sprinkled with talcum powder and the model standard is placed in it. The flask is positioned so that the rubber half-mold is at the bottom, and the second half of the model standard is filled with pieces of raw rubber. Then the rubber is vulcanized, resulting in two parts of the rubber mold. After this, the model standard is removed from the rubber mold and a sprue channel is cut into it. For simple jewelry models, it is enough to place the model standard between two rubber plates of the required thickness and vulcanize them under pressure. However, this method has a drawback - both rubber plates are "welded" together, and in order to extract the standard and then cast the wax model, it is necessary to cut the mold. Then the mold is thoroughly cleaned and lubricated with eucalyptus oil or a mixture of water and 77

glycerin. The model composition is pressed into a mold with a pressure of 0.2-1.5 kgf/cm2 at a temperature of 60-85 °C. The heating temperature of the mold should not exceed 35 °C. After pressing the mold is cooled in the refrigerator. Finished wax models are connected to the wax riser using wax pins. The mold is then placed on the rubber base. The model block is degreased by immersion in alcohol or carbon tetrachloride and air dried. You can also degrease the block in a soapy solution, followed by a rinse in cold water and air dry. Then the model block is poured with a refractory molding sand, which is processed in a vibro-vacuum installation. In the absence of a vibro-vacuum installation in the manufacture of jewelry from non-ferrous and precious metals at home, other methods can be used to obtain jewelry castings. Therefore, the investment casting process includes several stages, from the preparation of the model and half-mould to the pouring of the model block with the molding sand. Various methods and materials are used to achieve quality jewelry castings. To prepare the molding sand, it is necessary to mix a certain amount of sand and distilled water. Usually used from 0.32 to 0.42 liters of water per 1 kg of the mixture. This mixture is thoroughly mixed and placed in a vacuum chamber. Vacuuming is carried out at a pressure not exceeding 10 mm Hg and continues for 2-3 minutes to remove air from the mixture. The evacuated molding slurry is then poured into a metal flask. To ensure better consolidation and removal of the remaining air bubbles, the flask or several flasks are again evacuated for 2-3 minutes at a pressure of not more than 10 mm Hg. After that, the molding sand hardens, which usually takes about 40-60 minutes. After this time, the rubber seals are removed from the flasks and the molding sand is cut at the ends of the mold. Then the model composition is melted out of the mold. This can be done with steam or in an oven at 90 to 100°C for 1-3 hours. To ensure the strength and durability of casting molds, they must be calcined in special calcining furnaces. Piercing occurs according to a specific regime, which includes heating from 20 to 150 °C for 0.5 hours, holding at 150 °C for 3 hours, heating from 300 to 750 °C for 3 hours and holding at 750 °C within 3 hours. After that, the flasks are cooled at a rate of 2 °C in 1 minute. For the melting of silver alloys of grades SrM916 and SrM875, a certain procedure should be followed. First, a layer of calcined charcoal 5–10 mm thick is placed on the bottom of the crucible, and then the crucible is heated to a temperature of 950–1050 °C. Then silver and copper are added and the temperature is increased to 1000-1050 °C. The resulting melt is deoxidized with phosphorous copper in an amount of 0.1% by weight of the mixture and incubated for 2-3 minutes. After that, the slag is removed and the melt is stirred. As a result, the entire process of forming and melting molds requires precision and certain conditions in order to obtain quality products. When melting gold alloys of ZlSrM583-80 and ZlSrM750-150 grades, a special process is used, which includes the use of fused boric acid. To begin with, the crucible is heated to 1000 °C, and then the charge is loaded, which consists of waste, Ag-Cu ligature and pure metals. It is important to note that the waste of own production should not exceed 60% of the total mass of the charge. After loading the charge, the metal is heated to 1000-1100 ° C and the deoxidation process is carried out using phosphorous copper or zinc. The amount of phosphorous copper or zinc is 0.10% and 0.05%, respectively, by weight of the mixture. The melt is kept for 2-3 minutes, then the slag is removed and thoroughly mixed. The melting of ZlMNTs750 gold alloys is carried out in ceramic crucibles, since the use of graphite crucibles can lead to metal carbonization. First, the crucible is heated to 1000 °C, then 78

gold and the Cu-Ni-Zn ligature are loaded. All this is melted and heated to 1150-1200 ° C, after which the slag is removed and thoroughly mixed. Once molten gold is obtained, it can be used to fill calcined molds. This process can be carried out on installations for centrifugal casting or on installations "Vacuum-metal". A homemade electric melting furnace can be used to prepare liquid metal for these installations. However, the melting of gold alloys requires precise temperature control, the use of special crucibles and the addition of certain components to achieve the desired properties of the alloy. This process is an important link in the production of gold items and requires a professional approach to ensure high quality and efficiency. When pouring massive castings from alloys of grades SrM875, SrM916, ZlSrM583-80 and ZlSrM750-150, it is necessary to maintain the temperature of the casting molds in the range from 400 to 500 °C. For openwork castings from the same alloys, the temperature should be from 500 to 580 °C, and for castings from ZlMNTs750 alloy - from 500 to 600 °C. After pouring, molds filled with ZlMNTs750 alloy are cooled in air to room temperature, while for all other gold and silver alloys, cooling occurs in water. After cooling, the castings are knocked out and cleaned from the molding mass and chilled. Mold cleaning is performed using a 20-40% aqueous solution of hydrofluoric acid or a solution of Trilon B using ultrasound. For chilling castings from gold alloys, a 10% aqueous solution of nitric acid is used, and for castings from silver alloys, a 10% aqueous solution of sulfuric acid is used. The temperature of the solutions should not be lower than 60-70 °C, and the processing time should not exceed 5 minutes. After the completion of the process, the finished castings are analyzed for the content of the main elements and harmful impurities, and the surface condition and dimensions are also controlled. This is necessary to ensure quality and compliance. In addition, it is important to note that some types of foundry equipment can be assembled by yourself. This makes it possible to adapt the equipment to specific needs and production conditions. Formula for calculating the required weight of metal to create a block If we take the specific gravity of the wax as 1, then the following formula can be used to determine the weight of the metal: Р = Рв ρm + Рd. Here P denotes the weight of the required metal block, measured in grams; Pv - the weight of the wax block or Christmas tree, also measured in grams; ρm is the specific gravity of the metal, measured in grams per cubic centimeter; Rd is the additional amount of metal that is needed to fill the sprue bowl, also measured in grams. This formula allows us to determine the required weight of metal to create a block. However, beyond this formula, there are several other factors to consider when working with metals. For example, different types of metals may have different specific gravity, which will affect the final result. It is also important to consider the specific sprue and its shape in order to correctly determine the additional amount of metal required for filling. In addition, when working with metals, it is important to take into account the possible loss of material during melting and casting. These losses can be caused by metal evaporating or sticking to the gate walls. Therefore, it is recommended to use spare material to ensure that there is enough metal to fill the mold. 79

From this it follows that the formula P = Pv ρm + Rd is the basis for determining the weight of the metal, but when working with metals, other factors should be taken into account in order to obtain an accurate result and avoid material losses. During the process of pouring metal into the gating cup, the metal remains inside, forming a reservoir for castings. During the crystallization process, castings absorb metal from this reservoir. However, if the amount of metal is insufficient or the gate is defective, pores may appear in the castings. Determining the correct pour temperature Another problem occurs when there is a small amount of metal left in the sprue bowl and the riser (the vertical part of the casting mold) has less volume than the casting. In this case, the riser hardens before the castings and begins to pull metal out of them. This can lead to the formation of pores in the castings. To control the pouring process, it is important to determine the correct pouring temperature (Tc). For this, the following formula is used: Tz \u003d Tpl + (50-70 ° C) Tmelt is the melting temperature of the metal, taking into account heat loss during the pouring process. However, besides the casting temperature, it is also important to consider other factors that affect the quality of the castings. For example, pouring speed must be controlled to avoid turbulence and to keep the metal evenly distributed within the mold. It is also important to ensure that the casting cup is properly filled to avoid air bubbles or roughness on the surface of the casting. In order to achieve optimal quality of castings, it is necessary to carefully control all parameters of the pouring process and provide the right conditions for the crystallization of the metal inside the castings. This will avoid the formation of defects, such as pores, and obtain ideal castings with the required characteristics. When it comes to alloys, each alloy has its own unique characteristics, including data on the melting point of the metal and the flask. These data are usually presented in the form of tables that help us better understand the properties of various alloys. Below is a table with basic data on gold alloys of different samples, brass and silver. The table lists the melting points of these alloys, which helps jewelers and coin makers determine the optimal conditions for working with them. The table provides data on the melting points of various alloys of gold of different samples, brass and silver.

Metal

flasks

τ ,

°C

Gold

95 5 0-1040 50-670

Gold b.

10 6 25-1125 00-730

Gold

90 5 0-1000 50-670

Gold

10 5 00-1050 50-670

750 750 585 900

τ met , °C

80

Gold b. 585

11 5 50-1250 50-670

Gold 999.9

10 63

6 50

Brass

96 4 0-1040 50-650

Silver

95 4 0-1050 00-450

Various methods for calculating the charge When choosing and calculating the charge for precious metals, various factors must be taken into account. It is important to take into account the characteristics of each material that will be used in the charge, as well as their physicochemical properties. In addition, the smelting technique, the equipment used and the type of fuel used must be taken into account. All these factors significantly affect the loss of metals in the smelting process. To calculate the charge, it is necessary to have the following data: the chemical composition of the alloy to be prepared, the initial composition of the materials that will be used in the charge, and the amount of metal loss during the preparation of the alloy (waste). The chemical composition of the alloys and the allowable limits of the content of the components are determined by the technical conditions or GOSTs, and sometimes rely on the practical knowledge of experienced foundry workers. There are various methods for calculating the charge, and I will talk about some of them. One of the methods is the method of constant charge compositions. It is based on the assumption that the starting materials have a constant composition and can be used to calculate the charge. Another method is the method of equivalent proportions. It is based on balancing the equivalent proportions of the components in the charge. Another method is the method of normative proportions. In this case, standard values are used to determine the proportions of the components in the charge. Finally, the method of total losses involves taking into account the total losses of metals during melting to determine the composition of the charge. All these methods have their advantages and disadvantages, and the choice of a particular method depends on the specific situation and requirements of the smelting process. Charge calculation is a complex process requiring precision and attention to detail. However, the correct calculation of the charge makes it possible to achieve the desired chemical composition of the alloy and minimize the loss of metals during the melting process. Calculation of the charge for smelting an alloy of the 583rd test grade ZlSrM583 and its melting is an important task for amateur foundry workers. Sometimes situations arise when it is necessary to cast a product not from a finished alloy, but from individual components, such as pure metals, precious metal scrap or ligature. These components may be available from the caster or supplied by the customer. In such cases, the caster must be able to correctly calculate the composition of the charge to obtain the required alloy, for example, ZlSrM583-80. To begin with, it is necessary to carry out a detailed arithmetic calculation, taking into account the proportions and chemical composition of each charge component. This will 81

determine the required amount of each metal or master alloy in order to obtain the desired alloy. After the calculation, you can start mixing the components and subsequent melting. In addition, tabular data is available to help casters calculate charge rates for other alloys without having to do the math. These tables contain information about the proportions of the various components that are required to make a particular alloy. Such data is a useful tool for foundry workers to quickly determine the composition of the charge and start the melting process. It is important to note that correct charge calculation is a critical step in the alloy casting process. Incorrect proportions or poor quality components can lead to undesirable results such as defects in the product or incorrect physical properties of the alloy. Therefore, casters must have good knowledge and experience in charge calculation and mixing in order to achieve the desired quality and characteristics of the alloy. As a result, the ability to correctly calculate the charge for smelting an alloy is an important skill for amateur foundry. This requires an understanding of the chemical composition of the ingredients, proportions and mixing methods. This approach allows you to achieve the desired result and create a quality product from an alloy that meets the requirements of the customer or the caster's own preferences. Compound

Elements A u, %

Alloy composition accepted calculation

5

5

8

7.9

Composition of the Ag-Cu alloy

— 1 00

C u, %

8

for 8.3

Composition of waste

Gold, %

A g, %

3 4.7 3 4.1

1 9.2

7 0.8

—

—

Various methods for calculating the composition of the charge required for the production of alloys using centrifugal casting and casting using vacuum suction are an important part of the process of forming metal products, and their choice depends on the specific requirements and desired characteristics of the future alloy. First you need to choose a crucible with the capacity that will allow you to fill it with almost completely molten metal. This is important to ensure the correct ratio of components in the final alloy. Next, the crucible is subjected to heating to a temperature within 500°C to ensure uniform melting of the metal. The crucible loading process is carried out in a specific order to ensure that the alloy is formed correctly. Copper is placed at the bottom of the crucible, which may be due to specific requirements for the composition of the alloy. 82

Then a layer of silver is applied to the copper layer, and a layer of boric acid is poured on top of it. It is important to note that boric acid performs a number of functions, including protecting metal components from oxidation and enabling the necessary chemical reactions. After that, a layer of production waste is added to the layer of boric acid, which can also affect the properties of the alloy. And finally, a layer of gold is laid, which can be placed on top under a layer of boric acid. This step is especially important because gold does not oxidize at high temperatures. With a further increase in temperature to 1000°C, the metal between the layers of gold and copper melts. This molten metal sinks down, enveloping the copper, which promotes uniform mixing of the alloy components. However, when the temperature reaches 1100°C, the metal in the crucible becomes completely molten, and at this point it is important to gently stir it with a graphite rod to avoid segregation and ensure the uniformity of the alloy composition. Let us now consider the option of loading a crucible when melting an alloy such as ZlSrM585-80. First, in this case, gold in the form of ingots is loaded into the crucible. As the gold melts, silver and copper are added, mixing them thoroughly to achieve the desired ratio. Boric acid is poured onto the surface of the floating alloy, which forms a protective layer, covering the metal mirror and preventing its oxidation. These methods and the order in which the crucible is loaded may vary depending on the specific requirements of the alloy and its characteristics. Efficient control of the temperature and mixing process play an important role in the production of quality metal products with desired characteristics. To ensure a fast and safe process of melting the alloy, it is recommended to grind its pieces. This will avoid oxidation of the material. In addition, such processing of the alloy will help to compact the charge package and create a protective layer from atmospheric oxygen. In case the used amount of boric acid is not enough to completely cover the surface of the metal, which illustrates this situation. To solve this problem, it is recommended to add an additional amount of boric acid until the metal surface is completely covered. This will provide reliable protection against oxidation and preserve the quality of the alloy. Coating of melt surfaces with boric acid There are various methods for coating melt surfaces with boric acid. However, in some cases, a layer of charcoal is used instead of boric acid. This method is only recommended for smelting gold or copper. If the gold alloy contains platinum or nickel, then the use of charcoal as a coating is not recommended. There are also effective protective layers, which consist of molten salts of sodium chloride, barium chloride and potassium chloride. These layers provide reliable protection against oxidation of precious metals at temperatures up to 1300 °C. It is important to remember that the maximum temperature of the alloy should not exceed the melting point by more than 50-70 °C. Melting must be fast and efficient. Before pouring the alloy into the mold, it is recommended to add a fresh portion of boric acid. This makes it possible to reduce the viscosity of the alloy and lower its temperature. After that, the alloy is thoroughly mixed, and then the boric acid is removed. It is important to note that the use of various methods for coating and protecting the surface of the melt is an important aspect in the processing of precious metals. This helps to prevent oxidation and maintain the quality and purity of the metal. The correct choice of method depends on the composition of the alloy and the requirements of the melting process.

83

The melting of gold alloys with an open flame is carried out using gasoline and gas burners. The petrol burner consists of a pump that is activated by the foot. Air is supplied to the tank with gasoline through a tube, and passing through it, it is saturated with gasoline vapors, creating a torch in the gun. Air is injected into the burner, and the torch consists of a sharp blue "needle" with a yellow border. The temperature of the torch reaches 1150 °C, while the temperature of the yellow edging is 800-900 °C. These torches are ideal for melting metal weighing from 50 to 80 grams. For this, small bowls of fireclay clay are used, in which the metal is melted. However, in addition to using gasoline and gas burners, there are other methods for melting gold alloys. For example, electric melting is one of the alternative methods. In this case, gold alloys are placed in special ceramic cassettes, which are then placed in an electric furnace. When the furnace is turned on, an electric current flows through the cassettes, heating the gold alloys to the required melting temperature. Electric melting has several advantages over open flame melting. First, it provides more precise control over the temperature, which allows for more uniform melting of gold alloys. In addition, electric melting is less dangerous, since it does not require the use of an open flame. This reduces the risk of fire and ensures the safety of the work process. However, despite the advantages of electric smelting, open flame smelting is still widely used in some applications. For example, in the jewelry industry where small volumes of gold alloys need to be melted, petrol and gas torches remain popular due to their ease of use and portability. In addition, an open flame can create a special aesthetic effect that may be important for some artwork. Thus, open flame smelting of gold alloys is one of the common methods used in various industries, although there are alternative methods, such as electric smelting, which have their own advantages. The choice of method depends on the specific requirements and conditions of the smelting process. The scheme for using a gasoline-air burner to work with a melting bowl has several stages. To begin with, before melting begins, the melting bowl must be calcined and covered with a layer of borax to create protection against oxidation. Then gold or silver is placed in this bowl, which will be melted. It is important to add copper in small portions during the melting process to ensure uniform mixing of the metals. When adding copper, care should be taken to ensure that the flame of the burner has a blue color, and the melting bowl remains covered with borax. This allows you to maintain optimal conditions for the melting process and prevents the oxidation of metals. After the alloy is well mixed, a deoxidizing agent such as cadmium, zinc, or copper phosphorous must be added. These substances help improve the properties of the alloy and ensure its stability. Before pouring the metal into a mold, it should be kept in a molten state at a temperature exceeding the melting point of the alloy by 50-70 °C. This allows for easier and more uniform filling of the mold. The pouring of metal into the mold should be carried out at a slightly elevated temperature to avoid possible problems with deformation or cracks. As a result, the use of a gasoline-air burner in the scheme of melting metals makes it possible to achieve optimal conditions for obtaining a high-quality alloy. The firing and glazing of the melting bowl, the addition of copper and deoxidizer, and the correct melting and pouring temperatures are all important steps that ensure a successful result in the metalworking process. When melting white gold, a specially prepared alloy consisting of gold, palladium and silver is used. These components are first melted, then mixed and cooled to a solid state. 84

This alloy is called a ligature. During the main melting of white gold, the ligature is melted, and the top layer, which has not yet melted, is lifted up and pieces of zinc are placed. Zinc is added to increase the fluidity of the alloy. Then the temperature is raised until complete melting, and the alloy is brought to the required temperature for pouring. For melting white gold, acetylene or gas burners are usually used. The flame in these burners is formed by the combustion of butane or propane in oxygen. It is important that the flame is soft and well regulated, especially given the presence of palladium in the alloy. At home, a special vacuum device can be used to pour white gold. The vacuum device uses external pressure to ensure the correct filling process. It helps to avoid air bubbles or other defects on the surface of the product. Melting and casting white gold is a complex process that requires precision and skill. Every step in the smelting process must be carefully controlled in order to obtain a high quality product. With the right melting technique and the use of the right materials, beautiful and precious white gold jewelry can be created. The essence of the vacuum installation is to create a vacuum in the receiver by closing the damper. Then, with the help of a burner, the metal on the concave part of the bowl begins to melt. When the metal is completely melted, simultaneously with this handle, the shutter opens, the burner is removed, and the lid with wet asbestos is pressed against the bowl. Creating a vacuum is an important process in various fields such as physics, chemistry, electronics and many others. Vacuum plants are used to remove gases and vapors from a system, to create conditions for experiments in a controlled environment, or to ensure the correct operation of various devices. One of the key elements of the vacuum unit is the receiver, where the vacuum is created. This is a closed container in which a damper is installed to control the pressure. By closing the damper and using a special pump, a low pressure is created inside the receiver, which leads to the formation of a vacuum. A burner is used to achieve the required vacuum in the installation. It heats the metal on the concave part of the bowl until it melts. The melting metal emits gases and vapors, which are then removed from the system using the created vacuum. The molten metal also acts as a seal between the bowl and the lid. A cover with wet asbestos is used to ensure a reliable tight connection. Asbestos is able to absorb and hold gases, which helps to maintain the created vacuum. Pressing the asbestos lid against the bowl seals the system, preventing air infiltration and pressure build-up. Thus, the scheme of the vacuum device includes a receiver with a damper, a burner for melting metal, and a cover with wet asbestos to ensure tightness. This setup allows you to create and maintain the vacuum conditions necessary for conducting various experiments and ensuring the correct operation of various devices. Casting products from platinum, palladium and iridium by the Estrich process is a complex process that requires special equipment, melting and pouring technologies, and the use of specific materials. The melting point of these materials is very high, exceeding 1600 °C. In addition, when pouring such materials, there is a problem of high activity of the alloys at high temperature, which requires a controlled atmosphere or vacuum for their melting. However, most platinum group alloys do not require such difficult conditions. The main attention should be paid to materials that have high refractoriness and inertness. This avoids problems associated with high temperature and chemical reactivity of materials. To successfully master casting from refractory and reactive materials, researchers and engineers are working on the 85

development of new methods and materials. For example, special coatings and surface treatments are being developed that increase the refractoriness and inertness of materials. The possibility of using new alloys with a lower melting point, which will simplify the casting process, is also being explored. In addition, it is important to note that casting products from platinum, palladium and iridium by the Estrich process has a wide range of applications. These materials are used in jewelry, electronics, chemical industry, medical equipment and other industries. Due to their unique properties, they have high corrosion resistance, heat resistance and chemical inertness, which makes them indispensable materials in many areas. Thus, the development and improvement of platinum, palladium and iridium casting technologies is an important area of research and development. This will expand the possibilities of using these valuable materials and ensure their more efficient production. Form material

Tempera Form ture, °C material

Tempera ture, °C

Alumina, electrocorundum Al 2 O 3

2050

Titanium oxide TiO 2

1825

Chromium oxide Cr 2 O 3

2440

Silicon carbide SiC

2205

Chamotte (mullite) Al2O3 ∙ SiO 2

1830

Boron carbide B 4 C

2450

2800

Titanium carbide NiC

3250

2530

Zirconiu m carbide ZrC

3735

2980

Titanium nitride TiN

3205

Magnesium oxide MgO Beryllium

oxide

Calcium

oxide

Zirconium

oxide

BeO CaO ZrO 2 Zircon Zr ∙ SiO 4 Cerium oxide GeO 2

Graphite

2700

C Quartz

2430

SiO 2 Zirconiu m boride ZrB 2

2750

3650 1728 3040

Casting with stones is a modern way of making jewelry that is becoming more and more popular. One of the main reasons for this popularity is the convenience and security of the gems in the wax models used in the casting process. This method has found particular use in creating jewelry with synthetic stones such as cubic zirkonia, which do not lose their luster and color at the high temperatures required to pour the metal. The process of creating jewelry with stones begins with the manufacture of a master model, which will serve as the basis for the future wax model. For this, the craftsmen create a seat that exactly matches the size and shape of the inserted stone. This place includes teeth and facets, taking into account the shrinkage of the rubber that will be used in the process. The teeth, designed around the future stone, are carefully bent so as to ensure a secure fit. For prong setting, 86

a glass sample is used, which exactly repeats the shape of the inserted stone. This sample is carefully installed in the prepared seat in the model. Then, in order to fix the stone, the master model is heated to a temperature of 600–700 °C, after which it is abruptly immersed in water. This shock method results in cracking and shattering of the glass sample, which is then removed with a hammer. After the glass has been removed from the master model, the next step is to create a wax model. To do this, a rubber mold is made, which exactly repeats the future product with a stone. Stones are carefully fixed into the wax model, using its elasticity and flexibility of wax. Prongs are easily bent, and the stones are set in the desired position with the help of tweezers. The next step in the process of creating jewelry with stones is metal casting. The wax model, adorned with precious stones, is placed in a special mold for casting. The metal (usually gold or silver) is then melted and poured into a mold, where it solidifies and takes the form of a wax model. After the metal has completely solidified, the mold is dismantled, the wax model is removed and the last finishing work is carried out. This includes sanding, polishing and other procedures that give the product its final look and shine. As a result of this meticulous art and craftsmanship, the stone casting process results in magnificent pieces of jewelry adorned with stones of various shapes and sizes that remain securely set and delight their wearers with their beauty and brilliance for years to come. This method of making jewelry remains relevant and in demand in the world of jewelry. Setting the stone in wax prongs is one of the popular ways to secure gemstones to jewelry. However, this method has its drawbacks. Firstly, when installing a stone in wax, there is a risk of scratches on its surface. This can negatively affect the appearance of the product and its value. In addition, special wax must be used to set stones in wax prongs, which can be expensive and not always readily available. This can increase the cost of the jewelry making process. However, there is another method that allows you to cast jewelry with fixed stones - this is setting stones in a rubber mold. In this case, the stones are fixed in a specially created form of rubber. This method has its advantages. Firstly, the rubber form allows you to more accurately and safely fix the stones on the product. It provides reliable fixation of stones, preventing them from falling out or damage. Also, the use of a rubber mold allows the production of products with more complex and unique designs. Rubber is easy to model, which makes it possible to create a variety of shapes and contours for fixing stones. Another advantage of this method is its cost-effectiveness. A rubber mold is usually a more affordable and cost effective alternative to specialty wax. Thus, setting stones in a rubber mold offers a more convenient and reliable way to create jewelry with stones. It ensures the safety of stones, allows complex designs to be realized and saves production costs. The prong setting of stones in rubber molds is a process that requires care and attention to detail. First, a master model is created on which the stone is fixed. A rubber mold is then made and cut in such a way as to obtain a special cavity for the stone. The stone is carefully placed in this cavity, after which the mold is assembled. However, in order for the stone to be securely fixed, wax is used. Wax fills the mold, tightly fitting the stone and providing it with a secure fixation. It is important to note that when placing stones in a mold, it is necessary to pay attention to the correspondence of the edges of the stones and the edges of the mold. This will achieve the best result and ensure accurate positioning of the stone in the product.

87

It is also worth noting that the dimensions of the mold may change during the vulcanization process. If the stone in the master model has a diameter of 2 mm, then when placing it in the mold, it is necessary to take into account the reduction in the size of the mold and choose a stone with a diameter of 1.9 mm. This will avoid problems with improper placement of the stone and will ensure that the dimensions in the final product are exactly the same. In summary, prong setting stones in rubber molds is a complex and technically demanding process that requires attention to detail and precision. However, the correct execution of all stages allows to achieve high quality and reliability of setting stones, which is an important aspect in the production of jewelry. The mold half with the stone set is a special technique used in the production of jewelry with stones. To fill such products, a special mold called Stonecast is used. One of the main functions of this mass is to protect stones from damage caused by high temperatures during pouring. To prepare Stonecast, mix 100 parts of the powder with 38 parts of water. This ratio provides optimal conditions for protecting stones during annealing. When using Stonecast, the mold can be heat treated at temperatures up to 630°C without the risk of damaging the stones. While other masses without special additives can only withstand up to 500 ° C. Heat treatment of the mold is carried out in accordance with the schedule. This schedule allows you to determine the optimal parameters for each stage of the heat treatment process, ensuring stable and high-quality jewelry production. However, it should be remembered that the temperature of the poured metal also plays an important role. It should not exceed 550-600 °C in order to avoid undesirable effects and provide optimal conditions for pouring products. Thus, the use of a mold half with a set stone and a special Stonecast molding mass allows the production of jewelry with stones, while maintaining their integrity and quality at high temperatures. This is an important aspect in the production process that contributes to the creation of beautiful and durable jewelry.

88

X. Surface treatment of jewelry castings This is an important step in creating beautiful and shiny jewelry. Although finishing can be complex and require specialized equipment, some operations can also be performed at home. One of the available operations is annealing. It allows you to eliminate internal stresses in the metal and give it a stronger structure. To do this, the casting should be heated to a certain temperature and then cooled gradually. Another surface treatment method is pickling cleaning, which is especially suitable for silver items. Etching removes oxides and other impurities, restoring the luster and purity of the metal. Electrochemical polishing is another way to give a casting a perfectly smooth surface. This method is based on the use of electric current and special solutions that actively interact with the metal surface. Chemical coloring of gold is a process that allows you to change the color of a gold casting. With the help of special chemicals, various shades can be achieved, from pink to black gold. Mechanical polishing is a classic way to give a casting a mirror finish. Abrasive materials such as sanding paper or polishing pastes are used to remove roughness and scratches from the metal surface. Copying is a technique that allows you to create an exact copy of a casting. With the help of special molds and casting materials, it is possible to reproduce the original shape and details of the product. However, it is worth noting that some operations, such as holting and ultrasonic cleaning, require specialized equipment and are best performed in a professional workshop. It is important to remember that surface treatment of castings is a complex process that requires experience and care. Therefore, if you do not have enough experience or the necessary equipment, it is better to turn to professionals to get the perfect result. Annealing is a process in which a mold filled with material is heated to a certain temperature in a furnace and then cooled to room temperature. Often annealing is carried out in protective atmosphere furnaces to prevent oxidation or other undesirable reactions. However, it is more common in industrial plants where special handling of materials is required. Annealing has several purposes. First, it can improve the mechanical properties of a material, such as strength or hardness, by changing its microstructure. Second, annealing can eliminate internal stresses that occur in the material during processing, which helps prevent deformation or breakage of the product. In addition, annealing can be used to change the electrical, magnetic, or other properties of a material. After annealing is completed, the product usually goes through subsequent processing processes. It is dipped in water or other liquid to cool, after which it is washed and bleached. These additional steps may be necessary to remove annealing residues, as well as to give the product the desired appearance or surface properties. It is important to note that the annealing process may vary depending on the material and production requirements. For example, different annealing modes are used for steel, such as normalization, tempering, or recrystallization, depending on the desired properties of the final product. However, annealing is an important technological operation that improves the properties of materials and ensures the quality of manufactured products. It plays an important role in various industries including metallurgy, glass industry and semiconductor manufacturing. Bleaching of gold items is a process that is usually carried out by etching. For this, a 50% solution of sulfuric acid is used, which is heated to a boil in a glass dish. Then the product is removed from the acid, washed and dried. Sometimes a hot solution of sulfuric and hydrochloric 89

acids (mixed in a ratio of 50:50) is also used. This solution is considered more effective, since when heated to 80-100 ° C, it is able to remove oxides and molding mass residues that may remain on the surface of the product after casting. After bleaching, the castings are placed in a soda solution for a short time. If castings are left in a hydrochloric acid solution for more than 1 minute, they will turn brown. However, if you use a solution consisting of a mixture of sulfuric and nitric acid, diluted with 2-4 parts of water, gold items will have the color of pure gold. To bleach gold castings, you can use a 10% solution of nitric acid at a temperature of 60-70 ° C for 5 minutes. Under these conditions, the golden color will remain. However, if the product has a greengray tint after bleaching, it can be removed by mechanical polishing or by electrolysis. In addition, it is worth mentioning other methods of bleaching gold items. For example, solutions of peroxide or peroxide acid are sometimes used. These solutions have a strong oxidizing effect and can effectively remove oxides and impurities from the surface of gold items. There are also special whitening pastes and powders that are applied to the surface of the product and then removed. They contain chemicals that can break down oxides and other impurities, making gold shinier and pure. It is important to remember that bleaching gold items requires some skill and care, as the improper use of acids and other chemicals can damage the item. Therefore, it is recommended to contact a specialist or a jeweler to get professional help in whitening gold items. Silver products can be bleached and cleaned using special technologies. One common method is the use of sulfuric acid and potassium permanganate. The process begins with the addition of potassium permanganate to a 10% sulfuric acid solution, then the product is immersed in this solution. When potassium permanganate reacts with sulfuric acid, a sulfide film is formed that covers silver. To remove the formed sulfide film, the product is immersed in a solution consisting of a mixture of thiourea, alcohol and OP-7, dissolved in water. This mixture helps to effectively remove sulfides, restoring the luster of the silver. To prepare a soapy solution of thiourea, ethyl alcohol is added, which enhances its cleansing properties. There are also other methods of cleaning silver products. For example, you can use special silver cleaners that are available in stores. These products usually contain ingredients that can remove stains and restore shine to silver without the need for chemicals. They are easy to use and can be effective for everyday silver care. It is also worth noting that silver cleaning can be done using natural ingredients. For example, baking soda or lemon juice can be used to remove stains and restore silver shine. To do this, just apply a small amount of soda or squeezed lemon juice to a soft cloth and gently wipe the surface of the product. After that, rinse the product with water and wipe until completely dry. Thus, there are several ways to pickle and clean silver items. The choice of method depends on the preference and availability of the ingredients, as well as the degree of contamination and the condition of the products. Electrochemical polishing is one of the methods of surface treatment of metal products. It is often applied after a holting operation to give the product a smoother and shinier surface. However, if holting has not been carried out, electrochemical polishing can be performed using the following technology. First you need to prepare a large container or a jar with a wide ground stopper. Castings are then placed in the dish, and the container is filled with detergents, ceramic particles, shells and other abrasive materials. 90

It is recommended to observe the ratio of volumes: 1 part of the products to 8 parts of the filler. Detergents contain various ingredients such as detergent powders, soda, ammonia, sodium hydroxide and sodium chloride. These substances help remove contaminants from the surface of the product. The loaded container should be filled to 50-80% and shaken for a long time or placed on rotating rolls for 2-10 hours. This allows you to achieve a good polishing effect. After the polishing procedure, the product must be cleaned of flash and lubricated with a solution of detergents. At home, it is difficult to carry out a vibro-sharp, but if possible, you can use grinding, polishing and detergents, in which pieces of metal, balls, ceramic cones and other abrasive materials are placed. For electrochemical polishing in industry, special installations are used. Such an installation can be assembled independently and consists of a rectifier, a titanium plate, a product to be polished, and an electrolyte. The electrolyte ensures the conduction of electric current between the titanium plate and the product, which contributes to the electrochemical polishing process. Electrochemical polishing is an effective method for achieving high precision and smoothness of the surface of metal products. It is widely used in various industries, including automotive, medical equipment and jewelry. Through this process, the appearance and functionality of products can be improved, making it an important tool in the production and finishing of metal products. Gold of the 750th and 585th test can be painted in the color of pure gold using chemical coloring. To achieve the desired shade of color, the product must be boiled in a special solution for 2-3 minutes. This solution consists of 200 grams of potassium nitrate, 100 grams of table salt, 100 grams of hydrochloric acid and 50 grams of water. Before boiling, the solution should be stirred well to ensure vigorous evolution of chlorine gas. As a result of this process, the product will be cleaned of copper, and a small amount of gold will dissolve. After dyeing is completed, the product should be thoroughly rinsed in clean water using a brass brush moistened with beer or a solution of tartar. This will help remove grout residue and provide additional surface cleaning. Then the product must be dried by placing it in dry wood sawdust. This drying process will help avoid spots or damage to the surface of the gold. Chemically coloring gold is an effective way to change its appearance and give it a new hue. This process allows the creation of unique and original pieces of gold that can be tailored to each person's individual preferences and style. However, before applying chemical painting, it is necessary to make sure that it is safe and that the procedure is carried out correctly in order to avoid damage to the product or possible problems with its quality. Brushing is a process aimed at removing scale from the surface of a product, giving it a shine and removing burrs. For this, metal brushes with a wire about 0.08-0.1 mm2 thick are used. The brush disc rotates at 1500 rpm and has a diameter of 30 cm. However, in addition to the main characteristics, it is worth noting that brushing can be applied not only to metal products, but also to other materials such as plastic or wood. Depending on the type of material and the desired result, different types of brushes and speed settings can be used. Brushing has several advantages. Firstly, it allows you to remove oxidized layers from the surface of the product, which improves its appearance and prevents further corrosion. Secondly, the brushing process helps to remove burrs and burrs, which can be especially important for parts that require precision and smoothness. To achieve the best results when brushing, it is necessary 91

to take into account not only the parameters of the tools, but also to choose the right technique and pressure with which the process is carried out. In addition, it is important to ensure the safety of the worker using metal brushes by providing him with the necessary eye and hand protection. Thus, brushing is an important stage in the processing of surfaces of various products, providing them with cleanliness, shine and smoothness. Proper application of this process can significantly improve the quality and durability of products, as well as enhance their aesthetic appeal. Mechanical polishing is a process that can be performed on horizontal polishing machines. An electric drill can be used to drive such machines. Woolen or felt discs can be used as polishing wheels, which are lubricated with GOI paste. Also, felt, hair, cloth and thread discs can be used as polishing tools. The diameters of these discs usually range from 70 to 100 mm. To achieve the best result when polishing, various polishing pastes are used. Some of these include chromium oxide, paraffin, iron oxide, stearin, kerosene, oleic acid, and animal fats. The choice of paste depends on the material to be polished and the desired end result. The inner surfaces of jewelry require special attention when polishing. For this purpose, special tools called polishers are used. They are rods with a perfectly polished working end. Before use, the polisher is moistened with a solution of soda, soap or beer. When working with polishing pads, you can smooth out protrusions, scratches and other surface defects. Mechanical polishing is an important process for achieving a high quality finish on various products. It allows you to give the surface smoothness, shine and remove unwanted defects. By using different tools and polishing pastes, different results can be achieved depending on the requirements and desires. The plating bath is used for coating various items, especially jewelry. In this process, the electrical circuit plays an important role. The anode, which is made of copper, has a thickness of 3 to 10 mm. The voltage in the galvanic bath is from 1.2 to 2 V, and the current density is from 1 to 1 A/dm2. It is important to consider that the distance between the anode and cathode must be at least 100 mm. On the cathode, as a rule, hang a piece of jewelry that requires coating. To create the necessary voltage, you can use a rectifier, which can be assembled from an old radio transformer. This transformer must have an output voltage of 6 to 12 V. To limit the current in the rectifier circuit, you can connect a diode and a resistor in series. The resistor should have a resistance of 51 to 150 ohms. As a rectifier, you can use semiconductor diodes, such as D-303, D-304 and D-214. The electroplating technology described above involves the use of an external power source to apply silver and gold plating to jewelry. However, there is another technology that can be applied at home, but it is more labor intensive. This is the contact deposition of silver and gold in appropriate solutions without the use of a constant current source. Contact deposition of silver and gold requires a more complex procedure. First you need to prepare solutions of silver and gold, which will be used for coating. Then the object to be coated is placed in the solution, and a contact voltage is applied to it. This can be achieved by using a battery or other DC source. Contact application allows you to get thin and uniform coatings, but requires more time and effort.

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Thus, a galvanic bath is an electrical circuit in which the anode, cathode and current source play an important role. It can be used to apply silver and gold plating to jewelry. The choice between electroplating and contact coating depends on the availability of equipment and the desired result. Previously, various methods for applying electroplating to jewelry have been discussed. However, jewelers are sometimes faced with the task of copying items made from base metals, such as copper alloy. In such cases, the method of pre-growth of silver or gold plating can be used for economic reasons. Mercury coating However, before this, the product must be amalgamated, that is, covered with a mercury layer. This is necessary to equalize the potentials between silver and base metal to the potential level between silver and mercury. Thus, the surface of the product is prepared by an electrochemical method. This procedure is also performed before fire gilding and silvering to ensure a more durable finish. The composition of amalgam usually consists of 10 parts of mercury, 11 parts of nitric acid and 500 parts of water. To prepare an amalgam, mercury is poured into a porcelain cup, then nitric acid is added and the mixture is heated to a low temperature. If, after heating, the mercury residue remains undissolved, the solution is considered saturated. Thus, the use of amalgam prior to electroplating base metal jewelry is an important step in the process. This method improves the quality and strength of the coating, making the product more attractive and durable. The following reaction occurs: 3 Hg + 8 HNO 3 → ZN g (NO 3)2 + 4H2 O + 2 NO. After this, the solution is diluted with water. Coating technology is an important process that allows you to create a protective layer on the surface of the product. One method is to use a galvanic bath, where a well-cleaned and degreased product is attached to an electrode wire and immersed in a mercury nitrate solution for a few seconds. If the mercury coating is dense and uniform, the product is removed from the solution and rinsed in running water. Salt residues are removed in the silver bath. This plating method is based on ion exchange and is widely used in the jewelry industry. However, there are cases when it is impossible to use a constant autonomous current source. In such situations, the method of immersing the product in a bath with a temperature of about 90-95 ° C is used. At the same time, a thin metal deposit forms at the bottom of the bath, which serves as a coating for the product. Although this method is less efficient than using a constant current source, it has advantages in terms of cost savings and improved reliability. It is important to note that the choice of coating method depends on the required characteristics and features of a particular product. Galvanized coating provides a uniform and durable coating that protects the surface from corrosion and enhances its aesthetic appeal. It is widely used in various industries, including jewelry, electronics and automotive industries. New technologies are being researched and developed to improve the coating process. For example, electrochemical deposition methods have been developed that allow more precise control of the thickness and composition of the coating. This opens up new possibilities for 93

creating innovative materials with unique properties. Thus, coating technology is an important step in the production of products, providing them with protection and improving their appearance. Different methods, including electroplating and bath dipping, provide different options and benefits depending on specific conditions and process requirements. With continuous advances in technology, the future of coatings promises to be even more innovative and efficient. When it is necessary to obtain a thin silver coating on the product, it is placed in a bath with an electrolyte heated to a temperature of 85–95 °C. After a few seconds, a thin film of silver forms on the surface of the product. However, after the plating process is completed, the remaining silver in the bath must be removed, as the ions released from the surface of the jewelry will contaminate the electrolyte and shorten its life. After removing the product from the bath and achieving the desired color tone of the coating, it is washed and dried using sawdust or shavings. This helps to remove electrolyte residues and provide a uniform and high-quality coating on the surface of the product. This process allows the creation of aesthetically pleasing and durable silver plating on a variety of items. In addition, it is important to consider that for optimal results, it is necessary to control the temperature of the electrolyte and the time of immersion of the product in the bath. This allows you to achieve the desired shade and increase the strength of the coating. Thus, the process of electrochemical deposition of silver on products is an important and technically complex stage in their production. The contact method of coating metal products is based on the use of electrochemical principles and differences in potentials between the bath metal and the product itself. The main idea is that by connecting a metal product with a less noble metal, which is far from hydrogen in the electrochemical series, we increase the potential difference between the surface of the product and the bath metal. This, in turn, allows the metal to be deposited from the solution on the surface of the product. Let's look at this process with a specific example. Suppose we have a copper rod that we want to cover with a layer of silver. To do this, we wrap the copper rod with aluminum wire. Aluminum, when in solution, becomes an Al+ ion. In this process, aluminum displaces Ag+ ions from the ionic solution, resulting in the deposition of silver on the surface of both copper and aluminum. This process continues until both metals are in contact with the solution and a coating of silver is formed. However, it is important to note that the contact method process is completed only after both immersed metals have been passivated, when they are coated with a thin layer of the noble metal from the bath. This ensures the stability and durability of the coating. Now let's look at the advantages and disadvantages of the contact method. First, this method is easy to use and less sensitive to differences in solution concentration and the presence of impurities compared to the galvanic method. The galvanic method, for example, cannot be used for gilding products if tin was used in the process of soldering it, since tin can get into the electrolyte and affect the quality of the coating. However, it should be noted that the contact method is not economical to use, since the noble metal can only be used from the bath and not from the anode. In addition, the coating obtained by this method is often thin and uneven, which can be a disadvantage in some applications. Thus, the contact method is an effective method of coating metal products with noble metals, based on electrochemical principles. It has its own advantages and disadvantages, and 94

the choice of method depends on the specific requirements of the process and the quality of the coating. Contact silvering In this case, the following electrolyte is used: silver nitrate AgNO2 - 17 g, potassium cyanide KCN - 25 g; H2O water - 1l. Okay, here's the rewritten text with the addition of the new information: To carry out the silvering process, each serving of salt must be dissolved in 500 grams of water. Then the resulting solution should be carefully poured into the bath. To ensure reliable fixation of the product, it must be tightly wrapped with wire. It is important to leave the end of the wire long enough to hold the silver-plated item by it. Before starting the silvering process, the solution must be heated to a temperature of 85-90 degrees Celsius. The item is then placed in the solution bath and moved back and forth to ensure even coverage. It is important not to leave the product in the bath for too long, as this may cause discoloration of the surface. After the coating is achieved, the product is removed from the solution and freed from the wire. Then it is washed and cleaned, and then again wrapped with wire. The secondary winding of the wire should be placed in other places so that the coating is uniform over the entire surface of the product. Now you can repeat the silvering process several times to achieve the desired thickness of the coating. It is important to remember that each time the process is repeated, a new wire must be used, as during the silvering process it is passivated and becomes unsuitable for further use. This guarantees the quality and efficiency of the silvering process. Thus, the process of silvering products requires careful preparation of the solution, proper fixation of the product with wire, control of temperature and time in the bath, and the use of a new wire at each repetition of the process. These steps will help you achieve a uniform and high quality silver plating. Contact gilding For contact gilding, these prepared salt preparations are used. Their composition: gold chloride H[AuCl4] - 2 g; sodium sulfide Na2S - 10 g; potassium cyanide KCN - 5-10 g; sodium phosphate Na3PO4 - 60 g; H2O water - 1l. The gilding method, based on the use of these chemicals, involves their dissolution in heated water. This process is similar to contact silvering, but is used to cover items with white gold. Unlike red gold plating, less contact material and a lower bath temperature are required here. However, some problems may arise when gilding. For example, if a dark deposit appears during the coating process, this may indicate that the product has been in the bath for too long or 95

that the bath temperature was not high enough. In such cases, it is recommended to control the time spent by the product in the bath, as well as to ensure the optimum temperature in order to achieve the desired result. Gilding is one of the ways to give elegance and luxury to products. White gold plated in this way acquires luster and attractiveness, making the product more attractive to consumers. Moreover, this method allows you to achieve the desired effect using less material and the cost of heating the bath. However, it is important to remember that gilding is an art that requires certain skills and knowledge. To achieve a high-quality result, it is recommended to contact experienced specialists who can correctly carry out the gilding process and achieve the desired effect. Thus, gilding with white gold using these chemicals is an effective way to add luxury and appeal to products. Proper execution of the gilding process allows to achieve a high quality result and satisfy the needs of customers who prefer products with a noble and elegant appearance. Galvanic processes are an important part of many industrial plants. They allow different types of coatings to be applied to the surfaces of different materials such as metals, plastics and glass. However, for the efficient operation of an industrial enterprise, small galvanizing plants are not sufficient. To solve this problem, universal multi-purpose galvanizing plants are the most suitable option. They are installations in which four tubs are built into the table. This allows them to be used for various galvanic works, as well as for degreasing and washing surfaces. Universal multipurpose galvanic installations have a number of advantages. They allow you to smoothly change the voltage in the range from 0 to 10 V at a load of 100 A. This makes it possible to accurately control the electroplating process and achieve the desired results. To heat the baths in the installations, switching devices are used, which provide a stable temperature. Control over the process is carried out with the help of control lamps, which allow you to monitor the state of the baths. An alarm clock with second and minute hands ensures that the processing time in each bath is the same. Worker safety is also an important aspect when working with galvanizing installations. All baths are equipped with suction devices, which ensure the removal of harmful vapors and gases, protecting the health of workers. Additionally, multi-purpose universal galvanizing plants have a built-in chemical storage cabinet. This ensures the convenience and safety of storing the necessary reagents and chemicals. Thus, the use of universal multi-purpose galvanizing plants is an effective solution for industrial enterprises. They provide the possibility of carrying out various galvanic works, degreasing and washing surfaces, as well as guarantee safety and process control. Normal silvering The purpose of normal silvering is to obtain a durable, relatively thick silver coating. The surface of the product should turn out to be matte white, evenly covered with silver without spots and shiny spots. For this, a pure silver anode 1 mm thick is used. The size of the anode surface should be commensurate with the surface area of the product. In our case, when silvering jewelry (a small object), the anode is suspended so that it is only partially immersed in the bath solution. If the anode is too small, a higher voltage is needed, and the distance between the anodes must be increased in order to maintain their dissipation power. In general, as stated earlier, the distance between the anodes should be more than 10 cm. When the bath is in use, the anode should be a dull, light gray. De-energized white anode. In the idle state, the anode must be in the electrolyte. 96

Sequence of operations. After switching on the current, the product is attached to the cathode rod with a silver wire. First, the voltage rises to ~ 5-6 V. After obtaining a dense silver coating, they continue to work with normal operating voltage. If the product has been pre-silvered and brushed, it can immediately be silvered at normal operating voltage. After 15-20 minutes, it is removed, washed and brushed with brass brushes. The surface becomes shiny, and it is already possible to control whether the entire surface is covered with silver. Then the product is washed again in water. If the thickness is insufficient, then the described processes are repeated until the desired thickness is obtained. After the last brushing, the product is suspended for 3 minutes in a bath without current passing. Then the product is washed, dried and polished on cloth or felt polishing wheels. Sometimes the product has the following disadvantages: 1) it does not have a shiny surface, and it has to be polished; 2) low current density allows only slow metal deposition; 3) the surface of the coating is soft and wears off quickly. Possible defects in silvering are shown in the table. Possible defects in silvering Type defect

of

Reason appearance

for

Remedy

The product is Bubble (air) Degrease unsatisfactorily degreased and sediment and amalgamate amalgamated Uneven (rough) sediment Banded sediment

Filter the electrolyte

Soiled bath

Uneven amalgamation Degrease of the product and amalgamate The bath concentrated

is

too

Preheat the

The bath is too cold

bath

The edges of the product are rough

Too little metal content

Anode with a white-metallic sheen

Too much KCN

Dark spots on the anode, bluish-yellow sediment

Too little KCN

No sediment

The anode and product have no contact

97

Dilute the electrolyte with water

Add silver salts Add silver salts

Add 1-2 g/l KCN the

Clean contacts

Gray precipitate, evolution hydrogen

Reduce the Cathode current density current or hang of too high more products

Poor dissipation ability

Cathode current density Increase too low current density

Anode passive

Anode current density brushing too high anode

Poor dissipation ability

The distance between Distance the product and the anode is increase by at too small least 10 cm

There are several ways to improve the silvering process. First, you can add special brightening additives to the KCN bath, such as salts of selenium, tellurium, thiourea, carbon disulfide, and aluminum thiosulfate. These additives will help achieve a brighter and more uniform gloss on the surface of the products. Secondly, it is possible to abandon the use of cyanide as the basis of the electrolyte and make a bath of iodides, radonides, thiosulfates and other substances. This approach may be safer and more environmentally friendly, since cyanides are poisonous. Recent studies have shown that it is possible to significantly reduce the time of the silvering process. If earlier the process took about 3-4 hours, now thanks to the increased current density up to 1.2 A/dm2, it can be completed in just 30 minutes. This reduction in time can significantly increase the productivity and efficiency of the process. In addition, the new silver plating method makes it possible to produce products without the need to interrupt the process for brushing. The result is products without pores and bubbles, with a uniform gloss, high strength and low wear. This significantly improves the quality and durability of silver products. In general, thanks to new methods and technologies, the silvering process is becoming more efficient, safer and environmentally friendly. These improvements result in high quality products with excellent brilliance and durability, making silver plating more attractive to a variety of industries, including jewelry and electronics. Electroplating gilding, also known as normal gilding, is a process similar to silver plating. For this process, special bath compositions are used that contain certain chemical compounds. Many recipes for gilding can be found in the literature, and although they share some similarities, their use can be difficult for a jeweler without special knowledge of chemistry. However, if the technology is not followed correctly or there are deviations in the composition of the baths, significant losses of precious metals can occur. Therefore, it is recommended to use ready-made preparations and available baths, which are already quite effective and affordable. Currently, gilding baths are made up of various compounds, including potassium dicyanoauraate, which is the carrier of the precious metal, and potassium cyanide, which acts as "free" potassium cyanide. Sodium phosphate, which is a conductive salt, is added to increase electrical conductivity. Here are a few bath recipes that can be used for electroplating gilding:

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1. Potassium dicyanoauraate bath: - 5 grams of potassium dicyanoauraate - 100 milliliters of water - 1 gram of potassium cyanide - 2 grams of sodium phosphate 2. Potassium cyanide bath: - 3 grams of potassium cyanide - 50 milliliters of water - 2 grams of potassium dicyanoaurate - 1 gram of sodium phosphate 3. Sodium phosphate bath: - 4 grams of sodium phosphate - 75 milliliters of water - 1 gram of potassium dicyanoaurate - 2 grams of potassium cyanide It is important to remember that when using these baths, you must follow the technology and follow the instructions in order to achieve the desired gilding result. It is also recommended to use protective equipment and work in a well-ventilated area to avoid possible hazards associated with chemicals. Gilding process Gilding is a process in which a thin layer of gold is applied to the surface of a piece of jewelry. Various types of anodes are used for this, depending on the desired result. Soluble pure gold anodes, as well as insoluble platinum and stainless steel anodes, are widely used in normal gold plating. It is important that the area of the anodes is approximately 1/3 of the surface area of the products. When using a gold anode, the voltage can be set between 1 and 2 volts. However, for more efficient gold plating, it is recommended to use insoluble anodes, mainly platinum. If a stainless steel anode is used, the voltage should be set between 2 and 3 volts. It should be noted that preliminary gilding is carried out in the same way as the main gilding. The product is left in the bath until a dense coating of sufficient thickness is formed. However, it is not recommended to use an old gilding solution that has already been used, as in this case the precipitates formed are not completely covered during the main gilding process. In addition, there are other gilding methods such as cold gilding and hot gilding. Cold gilding is used to apply a thin layer of gold to the surface of items without the use of electrolysis. Hot gilding, in turn, is based on the use of special solutions that are heated to a certain temperature. In general, gold plating is an important process for creating gold-plated jewelry and other items. Proper selection of the anode and control of the voltage can achieve high quality gold plating and longevity of the plating. When gilding jewelry, the main requirement is a strictly defined bath temperature, which is in the range of 60-70 degrees Celsius. Also, a current must be immediately applied to the contact wire and the cathode suspended on clay. However, it is important to consider that the duration of gilding cannot be precisely determined and depends on several factors. The power of the bath, the desired quality of the surface of the coating, as well as the characteristic features of the product itself, can influence the gilding time. If the desired coating is to be glossy, then it should be done in less than 30 seconds. Otherwise, the product may become dull. An important point in the process of gilding is the thickness of the resulting coating. To obtain a solid thickness, it is enough to lower the product into the bath three times for 5 minutes. However, to avoid brushing residues from getting into the bath, after each brushing, it is necessary to rinse the product. The process of gilding, washing, brushing and re-gilding must be continued as many times as necessary to achieve the desired quality of coating. To achieve a metallic shine, brushing is sufficient, but a polished surface requires processing on a wheel made of linen and wool. There are defects in the gold plating process, some of which can be eliminated. 99

Defects can occur due to improper preparation of the surface of products, the ingress of foreign particles into the bath, as well as when the bath temperature is not high enough or the product is exposed to current for a long time. Methods for eliminating defects can be different: in some cases, it is necessary to wash the product, and in others - to polish it. However, the most obvious way to eliminate defects is to control the temperature of the bath and the duration of current exposure to the product. Thus, the gilding process is a complex and multi-stage process that requires several factors to be taken into account. It is important to remember to follow the technical documentation and properly prepare the surface of the product in order to obtain the ideal quality of the coating. Possible defects in gilding and how to eliminate them Type of defect

Reasons appearance

for

Chemical residues on the product

Spotted sediment

Remedy Clean the product

The amalgamation Dilute the solution is highly solution, carry out concentrated. The product amalgamation in a has been amalgamated for shorter time too long Pores in the base metal

Sanding polishing

and

Use metal that Poor durability in Base metal contains does not contain places phosphorus phosphorus Rough sediment

Bath is dirty

Filter the bath

bubble sediment

The product is poorly Degrease defatted product

the

red sediment

The bathtub is contaminated with copper impurities

Add 2-5 g/l KCN

Bath is slow

Bath is too thick

Dilute with water

Discolored, not Anode is too big or pure colored precipitate too small

Verify anode size

The bath works slowly, intensive formation of hydrogen. Sediment black-green

Too little gold content

Add golden salt

High ohmic resistance. Anodes turn brown

Too little KCN

Add 2-3 g/l KCN

Too little KCN

Add golden salt

Metallic anode

100

Rough sediment

Too much K 2 CO 3

The edges of the product are gray; coarseToo high grained brown-violet current density sediment; hydrogen production

Poor power

Too low scattering current density

cathode

cathode

Product-anode distance is too small

Add carbonatefree solution Increase the current or hang fewer products Increase current density Distance increase by at least 10 cm

There are special gold plating baths that are designed to overcome the disadvantages associated with the softness and rapid wear of gold platings. During the research process, many experiments were carried out aimed at increasing the hardness of the gold coating. One of the discoveries was that if gold is deposited together with a harder metal such as nickel, the overall hardness of the coating increases. However, such an operation cannot be performed at home, since special instruments and installations are required to select metals with the same deposition potentials. Thus, the process of gold precipitation using other metals is possible only in factories. There are also special baths for obtaining multi-colored gold. In a conventional bath, different shades of gold can be obtained by changing the conditions of metal deposition. For example, at high current density and bath temperature, as well as low potassium cyanide content, the precipitate will have a darker tint. When the ratio of parameters is reversed, light and faded precipitation is observed. More interesting results can be obtained by adding other metal salts to the bath. There are ready-made preparations that allow you to get different shades of precipitation, such as red, yellow, green and light yellow. Yellow and green gold require lower voltage and lower current density. The reactions take place at a temperature of about 70°C. The red gold bath requires a lot of energy and a higher temperature, around 80°C. Thus, special gilding baths make it possible to obtain a wear-resistant gold plating and various shades of gold, depending on the deposition conditions and the added metal salts. However, these processes require specialized equipment and professional conditions. Electrochemical peeling and polishing are two processes that have similar processing methods but differ in their purpose. Both processes use anodic etching, however their goals and applications are different. Electrochemical peeling is used to remove oxide films from the surface of products that are formed as a result of calcination. Also, this process helps to eliminate plaque that remains after the gold alloy is etched. Peeling in an electrolyte allows you to easily and quickly remove green deposits from the most inaccessible areas of the relief decoration. This eliminates the need for time-consuming operations such as the use of scrapers, sanding sticks or tensioned threads. However, after electrochemical peeling, the product still requires a little polishing in the usual way. On the other hand, electrochemical polishing is aimed at removing roughness and smoothing the surface of the product, as well as giving it a gloss, as in mechanical polishing. 101

This process is used to give the product a more attractive appearance and enhance its aesthetic characteristics. Polishing allows you to make the surface more even and smooth, eliminating minor defects and scratches. The advantages of electrochemical peeling and polishing lie in their efficiency and convenience. The flaking in the electrolyte makes it possible to quickly and easily remove deposits even in hard-to-reach places, which reduces the need for complex and time-consuming operations. Polishing helps to achieve a glossy surface and improve the appearance of the product. Both processes can be used together to achieve the best results. Thus, electrochemical peeling and polishing are important processes for product processing. They provide the removal of oxide films, deposits and irregularities, giving the surface a glossy look. These processes are efficient and convenient, allowing you to achieve high quality finishes without the need for complex and time-consuming operations. The anode pickling workflow involves using a bath at 80-90°C. In this case, the steel plate acts as a cathode and is connected to the cathode bus with a thick conductor. The product itself, which needs to be processed, is an anode and is mounted on a wire with a cross section of 4 mm2. The anode bar with the product and the wire is suspended freely, which allows it to be moved in the bath during the anode etching process. The current strength used in electrochemical peeling is 20-70 times higher than the current used in gilding, amounting to about 10 A/dm2, and the voltage increases 3-5 times, reaching 25 W. Moving the product in the bath takes about 30 seconds. The anodic etching process also helps to remove deposits and oxide films through the movement of liquids and gases. After peeling is complete, the product is left on the anode rod until the desired degree of electropolished surface is achieved. This method is most effective when working with high quality products such as 500 and above. However, in rare cases and with lower sample quality, this method may also be applicable. Strict adherence to the conditions is very important when using anodic etching to process white gold. This material requires a separate bath as it may tarnish and stain if processed with other materials. In addition, thin materials are not recommended for processing with this method, as they can be corroded through. In conclusion, anodic etching is an effective method for processing a variety of products, especially those that are of high quality and fineness. However, it is necessary to take into account the characteristics of the materials and correctly adjust the process parameters in order to achieve the desired result. Enameling is an art and technology that gives jewelry a unique aesthetic value and corrosion protection. Enamel is a fusible alloy of various colors, which is applied to the surface of the casting in powder form and then fired. Enamel not only decorates jewelry such as rings, brooches, pendants and much more, but also serves as a reliable protection against environmental influences. The composition of enamel includes various oxides such as silica and alumina, as well as other fluxes that give enamel its unique properties. The predominance of refractory compounds, such as silicon oxide, in the composition of enamel leads to partial crystallization and gives it a special texture and luster. On the other hand, fusible compounds such as sodium and potassium oxides can reduce the strength of the enamel. There are two main types of enamel: transparent and opaque (deaf). Clear enamels have a special translucency that allows the substrate they are applied to to be seen, adding depth and versatility to jewelry designs.

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Opaque enamels, on the other hand, have a denser texture and serve as an excellent background for various patterns and ornaments. To obtain colored enamels, the base alloy is first prepared, and then dyes are added to it. This process requires high technical precision in order to achieve the desired shade and color intensity. After the dyes are added, the alloy is remelted to ensure that the color is evenly distributed. Artistic enamels must meet a number of requirements. First, they must have a melting point of up to 800 °C, which allows them to be applied to metal substrates without the risk of deformation or damage. In addition, enamels must be chemically resistant to various conditions, including bleaching and moisture. Have good hiding power to create rich and vibrant colors, and adhesive power to provide a strong bond to metal. Finally, artistic enamels should always have a bright color and brilliance in order to give the jewelry a unique radiance. The enameling process includes several stages. The first stage is preparing the product. The product is thoroughly cleaned of contaminants and processed to remove oxides and other unwanted elements on the surface. It is then brushed to create good adhesion for the enamel. The next stage is applying enamel. Enamel, usually presented in the form of a powder with particles up to 0.01 mm in size, is evenly distributed over the surface of the product. It is important that the enamel powder be uniform in grain size to ensure an even coverage. Dust particles, which may arise during the break, are usually removed by washing the powder with water. And the last step is roasting. The product is subjected to high temperatures, usually in a special oven. During firing, the enamel melts and fuses with the metal base. This creates a strong and durable coating that retains its color and luster for many years. In conclusion, enameling is a unique art that allows you to create jewelry that is not only beautiful, but also durable. Enamel gives jewelry its vibrant colors, texture, and luster, making it a unique work of art. This process requires high technical precision and skill, but the results speak for themselves - enameled jewelry always attracts attention. Enamel is a material that is used to coat various products to give them a beautiful appearance and to protect them from corrosion. The process of applying enamel involves mixing ground enamel with water to form a slurry, which is then applied to the product with a brush or spatula. However, in order to achieve a good coating, it is very important that the expansion coefficient of the enamel is close to the expansion coefficient of the material on which it is applied. For example, gold is most suitable for casting and enamelling, as its expansion coefficient is close to that of enamel. However, on silver figurines that have come down to us, the enamel may be chipped to a greater or lesser extent, since the enamel does not adhere well to silver. In the case of gold cast figurines, the base material is modeled using enamel rather than gold. Gold serves only to create a base - a metal rod, which is then covered with a thick layer of enamel. In such products, enamel is present more than metal. This is due to the fact that this approach provides better adhesion of the enamel to the metal and prevents the occurrence of stresses in the metal. To reduce the tension that occurs at the interface between metal and enamel, enamel can be applied on small planes separated by cells and recesses. Thus, the ideal method is to cover the cast surface with enamel mixed with glue (tragacanth), which is applied to the product layer by layer with a brush or spatula. It is very important not to smooth the casting with a chasing, as this can greatly weaken the adhesion of the enamel to the metal. It is recommended to maintain the surface roughness of the casting, and, if necessary, to strengthen it by processing with a chisel. After applying the enamel, the product must be thoroughly dried and fired in a muffle furnace with an open spiral at a temperature of 600-800 °C. Enamelled jewelry is usually placed on special nickel or heat-resistant alloy stands with the enamel facing up to ensure even firing. 103

Thus, the enameling process requires accuracy and adherence to certain technological steps in order to achieve a high-quality coating and a strong connection between enamel and metal. Casters working in various fields are faced with the need to determine the sample of precious metals and their alloys. This is important both in production and in home workshops. For the successful manufacture of jewelry, it is necessary to know the qualitative and quantitative composition of the raw materials used, as well as to control the resulting product after all stages of its processing. Determination of a sample of precious metals in raw materials can be carried out using the method of destructive testing. This means that in order to obtain results, analysis must be performed, which may lead to some changes or damage to the sample. This approach can be applied if the goal is to obtain accurate data on the composition of the metal. However, when it comes to already made jewelry, it is desirable to use a non-destructive testing method. This allows analysis to be carried out without damaging or altering the product itself. In this case, various techniques are used, such as X-ray fluorescence, spectral analysis, and others, which allow you to determine the metal sample without harm to the product. Determining the fineness of precious metals is an important task for foundries and jewelers. This allows you to control the quality of the materials used in the manufacture of products, as well as guarantee compliance with requirements and standards. Thanks to various control methods, specialists can be sure that the resulting product will be of high quality and meet customer expectations. It is important to note that the determination of a sample of precious metals is a complex process that requires special knowledge and experience. Therefore, casters and jewelers must be careful and thorough when conducting control in order to avoid errors and shortcomings. Ultimately, the correct identification of metal assay ensures high quality and reliability of jewelry, which is an important success factor in this industry. A variety of instruments and chemicals are used to qualitatively and quantitatively analyze the precious metal in an alloy. One such tool is the touchstone, which is a black acid-resistant stone with a fine grained structure. It has a polished surface and is harder than precious metals and alloys. Another essential tool is the assay needle. It consists of a brass needle, at the end of which is soldered a small strip of an alloy of known purity. The assay needle is used to determine the fineness of the available gold in the alloy. To do this, you need to saw through a piece of alloy and drop nitric acid into it. The result of the reaction will help determine the composition of the alloy. If a green color appears at the cut, this indicates the presence of a copper-based alloy or gold plating. The pinkish-beige color indicates the presence of a silver alloy. If the reaction proceeds slowly and with a color change, then this may be due to the low purity of gold (below 333-carat) or the use of a non-precious alloy. If there is no reaction, this may indicate an alloy with a fineness of 500 or higher. For a more accurate analysis of the precious metal in the alloy, chemical reagents such as acids and their mixtures are also used. For example, aqua regia containing special acids can be used to determine the fineness of gold in an alloy. Gold chloride and silver nitrate are also used to help reveal the presence of these metals in the alloy. It is important to note that the analysis of a precious metal in an alloy requires experience and special skills. Professional gemologists and jewelers have the necessary knowledge and tools to conduct accurate and reliable analysis. This allows you to determine the quality and composition of the alloy, which is important in the manufacture of jewelry or the evaluation of the value of precious metals. 104

To analyze the gold content in a metal product, we need several tools. Take a file and gently clean a small surface of the product. Then, take a touchstone and draw it over the cleaned place until a line or stroke appears. The width of this line should be about 3-4 mm, and the length should be about 25-30 mm. Now that we have the stroke, we are ready to begin determining the gold content of the metal. Apply a drop of concentrated nitric acid to the stroke. Let's look at the reaction. If after 67 seconds the stroke is completely dissolved, this means that the tested metal is a gold alloy below 333 or does not contain gold at all. If the stroke turns brown, then the alloy can be classified as gold alloys from 333 to 500 samples. If the color of the stroke does not change within 6-7 seconds, we are dealing with a 585grade alloy. However, in addition to determining the gold content, we can also test for the presence of other noble metals in the sample. To do this, apply a drop of gold chloride to the cleaned surface of the product. If the color turns dark green within 1-2 seconds, this indicates the presence of pure or highgrade silver in the bar. In the event that gases appear during the reaction, we can assume that the metal is aluminum or its alloy. If the surface of the product turns black after 30-40 seconds, then this indicates that the ingot contains tin. Thus, after conducting these experiments, we will be able to determine the sample and composition of the metal product, as well as to identify the presence of gold and other precious metals in it. The test sample, which has a grayish-white color, can be identified by various chemical reactions. Here are a few options for determining the composition of a sample: 1. If no reaction occurs after applying gold chloride, then this may indicate the presence of a platinum bar. Platinum does not react with gold chloride. 2. If, after applying gold chloride, the bar first turns yellow and then turns black, then this may mean that the bar is made of zinc. Zinc oxidizes in the presence of gold chloride and forms a black precipitate. 3. If the color of the sample turns dirty yellow after applying gold chloride, this may indicate the presence of lead. Lead forms a characteristic yellow precipitate when reacted with gold chloride. In addition, the color of a sample can help determine its fineness (purity) and composition: - If gold chloride is applied to a gold alloy with a fineness greater than 585, the color of the sample will not change. If a faint spot remains, this may indicate a 583 alloy. - If the stain turns light brown, this may indicate a 500 alloy. A dark brown spot will appear on 375 alloy. Alloys below 375 will have a stain that will vary from chestnut to black. To determine the sample of alloys from 585 to 750, aqua regia is used. Alloy 950 does not change its color when heated to red heat and then cooled. An iodine stone is used to determine the purity and presence of platinum. Pure platinum does not react with iodide stone, while platinum alloys leave a dark residue on the touchstone. To determine the purity of silver, the following experiment can be carried out: silver is rubbed against a touchstone, and then the spot is moistened with a reactive liquid consisting of 16 parts of chromic acid and 32 parts of water. After that, the liquid is washed off. The purer the silver, the more intense the blood red color of the surface will be. Thus, with the help of various chemical reactions and experiments, it is possible to determine the composition and purity of the studied samples of a grayish-white color. 105

The touchstone is used to determine the hallmark of a piece of jewelry. To perform this procedure, a line 3-4 mm wide and 25 mm long is applied to the cleaned surface of the product. Then, at a distance of 2-3 mm from the line, strokes are carried out with a test needle on both sides of the test part. It is assumed that the metal of the item under test and the assay pin samples are the same. Next, a drop of assay reagent is applied to all strokes and the time required for the reaction is noted. After 15-20 minutes, the drop should be blotted with filter paper and observe the result. There are two possible outcomes: 1) If a darker spot remains on the line from the test alloy than on the line from the assay needle, then it can be concluded that the test alloy has a lower standard. 2) If the stains from the reagent on the marks from the assay needle and the test alloy coincide, then the sample of the test alloy is considered identical to the sample from the assay needle. In this case, the analysis should be carried out in daylight. This method allows you to determine the sample of metal in a piece of jewelry and determine its quality. It is widely used in the jewelry industry and helps consumers feel confident in the products they purchase.

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XI. Defects in jewelry castings and their elimination By following the correct technological processes, we can obtain castings that are as close as possible to the original in shape and size. These castings have a clean, smooth surface and require minimal machining. However, if the casting rules are violated, various defects arise, some of which can be corrected, and some of which cannot. Let's look at the essence of each defect in more detail. The first defect is underfilling, which manifests itself in the absence of a casting or part of it. This can happen if there is not enough molten metal to fill the mold completely. The second defect, burnt-on, is a deposit of metal on the surface of the casting, which has a rough structure. This defect usually occurs due to incorrect temperature of the molten metal or poor mold preparation. The third defect is cracks. They are cracks in the body of the casting and can arise due to stresses that arise during the cooling and compression of the metal. The fourth defect is non-casting; this is a discontinuity or layering of the casting. Such a defect can be caused by an incorrect distribution of the metal in the mold or a violation of the casting process. The fifth defect is flash. This is an incorrectly formed rim around the casting, which is often found when using lump molding. Flash can be caused by incorrect mold design or incorrect direction of molten metal flow. Finally, the sixth defect is porosity. It represents small depressions and shells, as well as their accumulations on the surface of the casting. Porosity is the main type of marriage when casting jewelry castings from precious metals. This defect may occur due to the presence of gas bubbles in the molten metal or improper casting techniques. To eliminate these defects, it is necessary to carry out additional operations, such as additional surface treatment, removal of burn marks, welding of cracks, etc. However, in some cases, the defects can be so severe that the casting has to be completely rejected. Therefore, in order to avoid defects in jewelry castings, it is necessary to strictly observe the technological regimes and properly prepare the molds. Only then will we be able to obtain high-quality and flawless castings that will delight us with their beauty and precision. Pores and cavities are mainly associated with shrinkage porosity and high gas content of the alloy. This can be caused by incorrect gate attachment, incomplete wax burnout, short burnout time, rapid heating of the mold when melting out the model composition, poor alloy composition, and high meltback rates. All these factors contribute to the formation of porosity in castings. To combat porosity, there are several recommendations that can help minimize its occurrence. First, it is worth striving for pouring metal with a low temperature. This can be achieved by raising the temperature of the mold and increasing the speed of rotation of the centrifugal machine. A lower pour temperature can help reduce the gas content of the alloy and reduce the chance of pore formation. In addition, it is important to develop an efficient gating system that will give the castings solidification direction. This will control the solidification process of the metal and reduce the possibility of pore formation. It is also important to avoid air pockets in the wax model as they can lead to porosity in the casting. However, it should be noted that removing porosity is a complex task and exact recommendations may vary depending on the specific situation. Each casting process requires an individual approach and optimization of parameters to achieve the best results. It is also important to pay attention to the composition of the alloy and to control the amount of return during melting. Poor alloy composition and a high amount of return can adversely affect the quality of castings and contribute to the formation of porosity. 107

In summary, to successfully produce castings without porosity, many factors must be taken into account, such as pouring temperature, gating system, alloy composition, and other parameters of the casting process. Only an integrated approach and continuous improvement can lead to high-quality castings without porosity. When measuring the temperature of the poured metal, it should be taken into account that an error of 50–100 °C is possible. This error can lead to marriage due to a change in the chemical composition of the alloy caused by the burnout of the ligature. In addition, at an elevated pouring temperature, the metal is gassed with oxygen from the air, which reduces its fluidity and affects the quality of the metal, leading to the formation of gas pores. At high temperatures, graphite crucibles can also fall off, and particles of graphite trapped in the alloy can cause pores. In addition, an increased crystallization temperature can lead to an increase in the grain size of the casting and the formation of cracks. Another cause of the problem is the oxidation of the metal in the mold. When metal comes into contact with the mold, burnout can occur, and this can lead to the formation of an enriched layer. Layers of copper oxides (CuO and Cu2O3) form on the surface of the casting, so pouring an overheated gold-silver-copper alloy can lead to severe oxidation of both the external and internal parts of the casting. With an increased copper content, oxidation can be even more pronounced, and as a result, internal zones can form in the casting. It is important to consider all these factors when working with high temperatures when pouring metals. The temperature must be controlled to avoid rejects and reduce the possibility of pores, cracks and oxides. Accurate measurements and the correct use of ligatures and molds will help ensure high-quality pouring and obtaining strong and defect-free castings. Casting defects Defect

Notch, scallops

outgro wth

Defect Definition Veins on the surface of the casting, resulting from the flow of metal into the cracks of the mold

Causes Cracks in the mold due to the increased content of the liquid phase, the use of a binder with a long shelf life, pushing the tooling, long-term holding of the gelled mold on the model, noncompliance with the technology for preparing the suspension, gelling it and firing the mold

Poor removal of air bubbles from the spherical slurry, inaccurate pouring of the slurry into protrusions the tool, poor lubrication of the model tool

Roughness, Rough sometimes rough, surface on the surface of the casting

Contaminated surface of the tooling, sticking of the suspension to the tooling due to poor lubrication, use of dirty filler

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XII. Production of individual jewelry Chains can be made in various ways: machine knitting, hand weaving and stamping. However, not all chain types can be made with all of these methods. Each method has its own advantages and disadvantages. Some types of weaving can only be done by hand, such as the intricate Bismarck. And thin and light chains, weighing about one gram, are almost always created using machine knitting. Machine knitting is one of the most popular ways to make chains. It allows you to automate the process and get high quality products. Chain knitting machines are usually equipped with special tools and devices that ensure accuracy and speed. Moreover, machine knitting allows you to create complex and patterned weaves that are difficult to do by hand. However, hand weaving also has its advantages. This method allows you to create unique and individual chains. Hand weaving requires great skill and patience, but the results can be unsurpassed. Hand weavers can use a variety of techniques and materials to create unique designs and textures. Unlike machine knitting and hand weaving, stamping is a more specialized way of making chains. Stamping allows chains to be created with specific shapes and textures that are difficult to achieve with other methods. This method is often used to create large chains or special designs. However, stamping requires special equipment and skills and is therefore used in a more limited number of cases. Thus, the choice of how chains are made depends on many factors, including the type and size of the chain, design, style and customer requirements. Each of the three methods has its own characteristics and capabilities, and it is important to choose the right method to create perfect chains. Machine knitting of chains is one of the most effective ways of producing jewelry. With the help of modern chain knitting machines it is possible to create light chains from very thin links. The thickness of the wire can be as low as 0.15 mm, which allows you to get products with incredible thinness and detail. However, despite the high efficiency and precision of machine knitting, such chains have their own special appearance. Unlike hand-stamped chains, machine-made chains look flatter and more voluminous. This can be both an advantage and a disadvantage, depending on the preferences and style of jewelry. In addition, the cost of machine chains depends on several factors. Firstly, these are the technical features of the machines used. More advanced and automated models allow you to create circuits faster and more accurately, but their cost may be higher. Secondly, the time spent on the production of the chain also affects its cost. Manual chains, which require more time and skill, may be more expensive than comparable machine chains. Thus, machine knitting of chains provides an opportunity to create jewelry with incredible precision and subtlety. However, they have their own unique visual structure and cost, which depends on various factors. The choice between machine and hand chains is always in the hands of the customer, who can choose the most suitable option for their needs and preferences. In the manufacture of gold anchor chains, the machine creates 600 links per minute. It is the amazing speed of production that allows us to meet the needs of our customers. However, despite the automation of the process, we also attach great importance to manual work.

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The finished chains are calcined in furnaces by heating up to 815 ° C in order to activate a special agent that solder the ends of the links. This process not only gives the chains strength, but also creates a special aesthetic finish. The quality of the machine weaving chain depends on the accuracy of the technological processes. We carefully control every stage of production in order to confidently provide our customers with high-quality products. The process of machine knitting of chains is illustrated by a video that can be viewed in the section on machine knitting in our article on types of chain weaving. This video allows our customers to get more detailed information about how our jewelry is made and what technologies we use. However, in addition to the machine process, we also attach great importance to the hand knitting of the chains. Our experienced craftsmen create unique and exquisite chains by hand, which cannot be reproduced with machines. This gives our customers the opportunity to purchase truly individual and unique jewelry. Hand weaving chains is considered the most reliable way to make them. The professionalism of jewelers is especially important, since their skill directly affects the durability and beauty of the product. For example, the correct selection of the diameter of the bolt and the thickness of the wire is a decisive factor in preventing breakage or poor bending of the chain links. Correcting such defects is almost impossible. However, hand weaving is not limited to small workshops, it is also used in large industries. This method allows you to make chains of various weights, starting from six grams. It should be noted that the process of hand weaving requires special techniques and experience in order to achieve the perfect result. It is important to understand that hand chain weaving is an art that requires careful control and attention to detail. Each link must be carefully connected to ensure strength and reliability. Each wire must be carefully secured to prevent it from breaking or falling out of the chain. Thus, manual weaving of chains not only ensures high reliability of the product, but also gives it uniqueness and individuality. This method requires skill and professionalism and is an integral part of the jewelry art. Stamped chains are one of the most popular jewelry options. They are made using special punching dies, which push through sheet metal. A distinctive feature of stamped chains is their connection method - the links of the chain are threaded into each other, and not soldered. This production method allows to achieve high strength and durability of products. However, despite their advantages, stamped chains have some disadvantages. First, they look a bit bulkier and heavier than their actual weight, which can be annoying for some people. Secondly, when worn, stamped jewelry turns out to be capricious - it is easy to deform them, and it is problematic to repair them. That is why it is recommended to remove stamped chains before going to bed to prevent damage. However, stamped chains remain a popular and affordable piece of jewelry that can highlight each person's style and personality. The manufacture of hollow chains is a complex and technologically complex process. Some people call them "inflated" chains. Currently they are very popular. To create a quality product that can be worn daily without fear of deformation, special equipment and strict adherence to technology are required. One of the main advantages of hollow chains is that they look very large and fashionable, but they weigh much less than their solid counterparts. This makes them more affordable. Some well-known stores where hollow chains can be purchased include goldlines44.ru and jewelry-gorod.rf. There are also other options for hollow gold, such 110

as serdza.ru. All of them offer a wide range of styles and designs so that everyone can find the perfect decoration for themselves. Inside such a chain there is a special device - an "empty body", which is achieved through the use of a special core made of base metal, such as iron. This core is wrapped in a precious metal plate and then goes through an acid pickling process to remove the inside. This is important because if the etching technique is not followed, iron residues may remain, which can reduce the quality and fineness of the product. However, with proper production, jewelers always try to place the seam on the inside of the chain link in such a way that it is barely visible. This provides higher quality and aesthetic satisfaction for the buyers. Thus, the "empty body" within the chain is an important element in jewelry making that requires meticulous attention to detail and the use of specialized techniques. Hollow jewelry is created using various technologies and processes. First of all, the wire is rolled and annealed to achieve the desired metal structure. The chain links are then soldered together to create a beautiful and unique piece of jewelry. Some hollow chains can be diamond cut and chipped to give them extra brilliance and elegance. But the very last step is etching the core, which makes the chain bare on the inside. But despite all the technological improvements, hollow chains still require special care when wearing. Link deformation can lead to serious problems and it may not be possible to restore or repair the chain. Therefore, in order to prolong the service life of a hollow decoration, it is necessary to monitor its safety and handle it carefully. After all, this is the only way to enjoy its beauty and elegance for many years. The diamond cut and the twisted chains are what make the jewelry so sophisticated and eye-catching. Diamond-cut18 chains turn into real jewelry masterpieces. But what is diamond cutting and how is it produced? This process involves the use of a special machine on which diamond edges are applied. The chamfer can be beveled on all sides of the chain link to make it sparkle brighter and attract attention. Each link in the chain gets multiple facets that reflect the light and create amazing sparkle. Diamond cutting is especially popular on armored chains and Bismarcks. This type of processing allows you to change the appearance of the chain beyond recognition and give it a unique style. As a result, the chain becomes a unique decoration that attracts the admiration and delight of others. Therefore, if you want to purchase a piece of jewelry that will stand out from others, pay attention to diamond-cut chains. They will make your look unique and elegant. There are many ways to process chains, and one of the most popular is the "skew" technology. It allows you to create chains with different weaves that differ significantly from the original weave and offer a huge variety of looks. The essence of this technology is to change the thickness and width of the links by compressing them on a special press. The press can have various dies that allow the chains to be cut into a variety of cross-sectional shapes, such as round or rectangular. The compression force can reach up to 30 tons, which makes the chains very dense and rigid. When choosing a chain, you need to take into account their features. Making earrings is a fascinating creative process. To create unique jewelry, it is necessary to take into account not only their structure and design, but also the features of the earrings. Earrings consist of the front part, which includes the castes and the top. However, the most distinctive feature of these jewelry is the earring devices or locks. Depending on your preferences and style, you can choose different types of earring devices. For example, hanging hooks, which are the easiest to manufacture. To create them, you need a wire blank of a certain thickness and length. The hook usually has an average diameter of about 8 mm, so a workpiece that exceeds this diameter is used for work. In addition, the blank must be long enough to create the earring 18

Diamond cut is a style or design guide used when shaping a diamond for polishing, such as the brilliant cut.

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itself. This approach allows you to create elegant and stylish earrings that will delight their owner. It is important to consider that every detail of the earring plays a role in creating its overall image. Therefore, when making earrings, it is necessary to take into account all the nuances and features in order to get the perfect result. Do not forget that each accessory has its own style and character, so when creating earrings, you need to choose a unique design that will reflect the personality and taste of its owner. To make casts or tops, the desired size of straight wire is first cut, which is then soldered into the cast or top. In the manufacture of caste, a hole is drilled or pierced at the level of the welt to strengthen the workpiece in a special fixture. It is important that the diameter of the hole matches the thickness of the wire. If a low cast or overlay is used, to which the hook should be soldered, then with the help of a needle file, a groove is made on the base into which the end of the wire is soldered. In case a cast or low-welded tip is used, the blank is soldered between the welt and the tip, after which the blank is soldered. This process ensures that the wire is securely connected to the custom or tip and guarantees the strength of the structure. In the manufacture of piece products, the place of soldering must be filled. To do this, if a hook without a loop is used, it is bent. Manually, using a round rod with a diameter of 8 mm, the hook is bent in the manufacture of piece products. However, in the manufacture of a large batch, the bending process is carried out using a special device in the form of a lever. If a hook with a loop lock is used in the earring, the lock is soldered to the hook before it is bent. The loop lock consists of two parts - a hinge and a loop inserted into it. The hinge is a piece of tube with an inner diameter of 0.6-0.8 mm and a length of 2.5-3.0 mm. It is soldered with a fugue to the welt or cast from the side of the base and strictly opposite the hook. The hinge should be soldered perpendicular to the hook, ensuring a secure connection. Correct bending of hooks and soldering of locks are important steps in the production of jewelry. They guarantee the strength and reliability of the design, as well as ease of use for the end user. Therefore, it is important to pay due attention to these processes and use the right tools and techniques to achieve the desired result. To make a loop, the wire is annealed and rolled off so that it freely passes into the hinge hole. Wire length 12-015 mm. Its ends in the threaded state are retracted at an angle and soldered. The hook is bent and adjusted in length only after the loop lock on the earring is assembled. The length of the hook depends on the distance of the loop folded down. On the outside of the hook, you need to make a shallow cut. Paired earrings are scraped after they are fully processed. Earrings are one of the most secure types of earring clasps. They provide a secure fixation of the earrings on the ear and prevent them from falling out. Jewelry earrings are made of high quality materials such as silver or gold and have an elegant design. They are suitable for any style and can be decorated with stones or other decorative elements. Spring locks are the most reliable, but they are the most difficult to manufacture. They need to be collected directly on the back of the top or cast. The locks consist of two parts: a spring hook and a fastener. Shvenza are divided into two types: jewelry and haberdashery. Haberdashery fasteners, unlike jewelry, are designed for everyday wear and are often used in mass production of jewelry. They are usually made from cheap materials such as stainless steel or plastic. Haberdashery fasteners can have various shapes and colors, which makes them more affordable and diverse for buyers. So, the choice of lock for earrings depends on the preferences and requirements of each person. Jewelry earrings are suitable for special occasions or emphasize the status of the owner, while haberdashery earrings are a more affordable option for everyday use. It is important to choose a lock that provides comfort and security when wearing earrings. 112

Making a spring hook directly on an earring is a process that requires certain skills and tools. First of all, a wire blank with a diameter of about 1 mm is taken. Then the desired piece is cut off from the workpiece, which will be used to make the hook. This piece is soldered to the cast or top of the earring. The distance from the tip to the kalena of the hook is usually 2 to 10 mm. It is important to take this into account when manufacturing, so that the hook looks aesthetically pleasing and is worn comfortably. When the desired length of the hook is measured, it should be bent. If sharp hardening is required, the wire is cut from the inside with a sharp needle file, then it is bent, and the cutting is soldered. In the case of a smooth bend, bending is carried out on a special fixture or manually using pliers. Making a spring hook on an earring is a delicate art that requires attention to detail and professional skills. It is important to be able to measure and bend the wire correctly in order to create a comfortable and beautiful hook. In addition, it is also necessary to take into account the size and shape of the earring itself, so that the hook fits harmoniously into the overall design of the jewelry. Making an earring is a process that requires absolute precision and total involvement from the artist. The first step is to make a hook, for which you need to bend the wire at a certain angle. It is important to remember that the angle of the bend must be slightly more than 90° in order for the hook to hold well on the ear. After bending the wire, the next step is to mark the total length of the hook. Usually this length is 10 mm. Then the end of the hook is flattened from the sides and a mark is made on it of the finishing length of the hook, that is, the distance from the kalena to the hook. Typically, the finished length of the hook is approximately 7.5-8 mm. However, the most difficult detail in the manufacture of an earring is a jewelry fastener. Its dimensions depend on the height of the top along with the hook. To get a fastener, you need to take a piece or an ingot of gold and roll it until a square profile with a side of 2.2-2.5 mm is obtained. And, finally, a hook-hook is put in place of the mark and processing is carried out. The whole process of making an earring requires skill and care to get a beautiful and unique ear piece. The length of the fastener is determined by the need to take into account the elongation of the workpiece during the rolling process. To create a pair of fasteners, a blank of double length is taken. Each fastener consists of two elements: a beak and a tail, which are connected by a movable pin. The beak is the main support for the entire fastener, so it has a larger diameter. The tail gradually tapers towards the hook. In the middle of the shvenza, there is a section equal to the total length of two beaks, approximately 20 mm. The ends of the blank are rolled in flat rolls until a thickness of approximately 1.0-1.2 mm is reached. It is important to consider that the length of the fastener plays a key role in its functionality. When rolling, the workpiece will stretch, so this factor must be taken into account when determining the length. Paired earwires allow for a secure connection and aesthetic harmony. The components of the fasteners, beak and tail, have their own characteristics. The beak, which is the supporting base, has a larger diameter to ensure the stability and strength of the entire structure. The tail, on the other hand, is thinner and gradually tapers towards the hook, providing ease of use and aesthetic appeal.

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When marking the fasteners, it is important to note the area in the middle, which is equal to the total length of the two beaks. This allows you to accurately determine the position of the pin and ensure the correct connection of the parts. The remaining ends of the workpiece are rolled to achieve the required thickness. This process is carried out in flat rolls, guaranteeing uniform compression and a perfectly shaped billet. To start the manufacturing process, the workpiece is cut into two parts. However, before that, there are some important details to consider. The angle of the beak should be a continuation of the angle of the caste or welt, and also match the pattern of the earring and the shape of the caste or top. When applying a workpiece with a bent beak to the cast or welt of the top, it is important to ensure that it is on the opposite side of the hook and is in the right position for subsequent soldering. When all the parts are assembled, special attention should be paid to the tail of the earring. It must be parallel to the base of the cast or welt to ensure a proper and secure connection. To do this, the shvenza is cut with a jigsaw into two parts - a beak and a tail. At the same time, it is important to choose such an angle of dissection so that the largest areas of their contact are formed, and also to ensure free breaking of the fasteners outward during pin connection. In order to avoid mixing up parts and not having to re-adjust the pads of adjacent parts, it is important to monitor the correct assembly. One way to ensure an accurate connection is to create lateral slots in adjacent plates using a thick jigsaw blade. These slots are made at the same angle and after that the flat-rolled plate is fitted to them. When the plate fits exactly into the slot of the shank and is soldered, it is necessary to fit the remaining free part of the flag into the slot of the beak. This will allow you to combine the details of the fasteners without a gap. To fix the parts, shellac is used, which is heated to its melting point. Thus, the parts are firmly fastened and a reliable connection is ensured. However, it is important to remember that the process of fitting and fixing parts requires care and precision. In the event of incorrect assembly or insufficient fit, connection problems may occur and the need to rework. Therefore, sufficient time and attention should be given to each step of the process to avoid unforeseen problems in the future. Before proceeding with the installation of fasteners, it is necessary to determine the desired level on the hook. Then, a lock hole is made in the shank of the fastener. After that, the fastener can be put back in place by fastening it with a hook. For a more secure fixation, the base of the beak is soldered to the caste or welt of the top. When soldering, the shellac used for fixing burns out on its own, filling the gaps. After that, the earrings undergo final processing, including dressing of solder joints and scraping. Shellac, after hardening, in the beak, allows you to drill a hole of the desired diameter in the fastener so that it passes through the middle of the inserted plate. Then, the parts are pinned for additional fixation. After that, the shwenza is finally processed, straightened, filed and scraped. Making brooches and pendants is an activity that requires attention to detail and the ability to work with different materials. But before you start creating jewelry, you need to understand their structure and constituent parts. All brooches consist of two main parts: front and lock. The front part of the brooch is what will be visible from the outside and attract attention. It can be made in the form of a stone or gem cast, or it can be an elegant top. The tops of the brooches can be cut or cut to create a variety of designs and styles. The locking part of the brooch is what ensures its secure attachment to clothing. It includes a clasp that connects to the front through a hinge or welt. The lock is an important component of the lock part, which ensures the safe fastening of the brooch. Depending on the type of lock, it 114

can be open or closed. An open lock is a wire hook, under the loop of which a needle is wound. A closed lock protects the needle from spontaneous unfastening and is divided into several types, including ramrod, visor and revolver. In the process of making brooches and pendants, it is important to take into account all these details and choose the right materials and work techniques. Not only the convenience of using the brooch, but also its reliability depends on the choice of the lock. That is why many craftsmen prefer to use ramrod locks, which are considered the most reliable and safe. Thus, making brooches and pendants is a fascinating and creative work that requires attention to detail and the ability to work with different materials. It is a process in which each component plays its part, creating unique and attractive jewelry. Whether it's a front part with stones or a top, or a castle part with different types of locks - every detail matters and contributes to the overall image of the decoration. In the process of creating a brooch, the location of the needle is an important element, which depends on the shape of the brooch itself and the intention of the jeweler. It can be placed along the entire length of the product to give it stability. However, if the brooch has an openwork design with a visible pattern or a transparent stone, then the movable needle joint will be placed in such a way that it is least visible to the viewer's eye. The assembly of the brooch begins with the hinged connection of the needle with the brooch itself. This process typically uses a low hinge made from a thin-walled tubular billet with an inside diameter of 0.6-0.8 mm. But the creation of a brooch is not only an assembly process, but also a manifestation of a creative idea. Each master jeweler puts his own idea and tries to give the product a special aesthetic value. As a result, the brooch becomes a unique piece of jewelry that reflects the personality of its creator. Making a brooch requires meticulous work and attention to detail. The first step is to solder the piece to the welt or top of the brooch. This ensures a strong connection between the workpiece and the base of the brooch. When the workpiece is attached, the next step is to mark the middle part on the workpiece, which will be movable. This is important so that the hinge works flawlessly and allows the brooch to move freely. After marking the middle part, a needle is soldered on the tube, which is equal in length to the movable part of the hinge. For the manufacture of the needle, a wire 1.2 mm thick is used. Its length is determined by the size of the brooch, which guarantees the correct ratio between the needle and the brooch. To ensure the stability of the needle and prevent it from dropping, a stop is made, which is soldered at the junction of the needle with the hinge. This is an important detail that ensures the correct position of the needle in the closed state, parallel to the welt or the base of the tip. Thus, making a brooch requires not only the ability to work with materials, but also attention to detail in order to achieve the perfect hinge and functionality of the brooch. First, a section for a hinge is cut out on the workpiece, which is then replaced by a movable hinge with a needle. The hinge axis is a pin that is inserted without rivets to check the operation of the needle. If done correctly, the needle should swing back 90° from its initial closed position. A ramrod lock is assembled immediately on the brooch. It consists of a tube that closes the end of the needle, and a ferrule, which is another tube. The outer element, the ramrod guide, is also part of this lock. 115

In the process of making a brooch, step by step, certain instructions should be followed. First, it is necessary to make a blank from thin-walled metal, the diameter of which is 0.25-0.3 mm. The main parameters of the workpiece depend on the diameter of the ramrod and the section of the pointed end of the fastener. To do this, cut off the clip with a length of 7-8 mm, and the length of the ramrod should be 2-3 mm longer than the length of the clip. However, each brooch is unique, so the size and shape of the clip is calculated individually for each item. After manufacturing the workpiece, solder the clip onto the support post of the lock. To do this, it is necessary to determine the length of the rack, depending on the length of the clip. The shape of the rack must be designed in such a way as to ensure a secure fastening of the lock. By soldering the post to the top and the welt at the same time, a strong connection can be achieved. Thus, the process of making a brooch requires care and precision in every step. The dimensions and shape of the blank, as well as soldering the clip to the lock stand, play an important role in creating a high-quality and durable product. In the process of assembling the visor lock, the stand is soldered to the brooch on the opposite side of the hinge in the direction of the needle. This allows the lock to function properly. Then a clip is attached to the rack and soldered, which has a groove cut on one of the sides. This groove is necessary to move the ramrod within the lock. The width of the groove is approximately 0.5-0.6 mm, and its length is equal to 2/3 of the length of the clip. After filling the groove, a stop is soldered on the ramrod, which ensures the correct position of the ramrod inside the clip. However, the needle is only pinned after the final assembly of the lock in order to avoid damage or deformation. The basis of the visor lock is its core, which consists of a tube of a certain shape and size. The core blank has a length of 2 mm, an inner diameter of 0.7-0.8 mm and a wall thickness of 0.3-0.4 mm. The trigger, which is the stop, is soldered to the center of the core tangentially to the reveal, across the direction of the tube. This arrangement of the trigger ensures the reliability and ease of use of the visor lock. In the operation of a revolving lock, there is a similar principle to that described above. It also consists of a core and a body, but differs from it in size and manufacturing method. One of the types of jewelry is pendants. The pendant of the pendant can be made from a caste with a stone or from a top with stones, as well as without them. Making pendants is similar to the process of making other jewelry tops. However, a distinctive feature of the pendant is the presence of a hanging ear. The pendant usually has two lugs: a hanging eye, which allows the pendant to be held on a chain, and a connecting eye, which connects the pendant to the hanging eye. The hanging ear can be different: simple (wire) or shaped, with a front plate on which one or more stones can be fixed. First you need to make a shaped eye for the pendant. For this, a wire of a certain section and diameter is used. The manufacture of the eyelet begins with the processing of the lining, while leaving only the engraving or setting of the stones open. Then the pendant is soldered to the connecting ear from above. When choosing a place for soldering, it should be taken into account that the suspension does not rotate under the weight of the stone, but remains vertical. The center of gravity of the pendant is at the bottom, so it is important to properly position and solder the eyelet. The material for the connecting ear must be strong and reliable so that the pendant does not come off during use. Wire with a cross section of 0.8 to 1.2 mm and an inner diameter of 1 to 2 mm is ideal for this purpose. Thus, the process of making a pendant ear requires precision and accuracy in order to create a beautiful and functional piece of jewelry.

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When assembling the shaped hanging eyelet, the half eyelet is soldered to the back side of the lining. This is an important step, as the half-lug, combined with the overlay, forms the desired shape of the ear. But the process is not limited only to this: after soldering one end of the halfear to the overlay, the other end also needs to be soldered. This is done at a later stage when the ear is fully assembled. Thus, each step in the suspension lug assembly process has its own important role and requires precision and accuracy. Bracelets, depending on their design, can be rigid or composite. Rigid bracelets, such as a hoop or brace, are made by stamping or mechanically, as they are difficult to make by hand. Composite bracelets, in turn, consist of several groups of links connected by hinges. The bracelets are made using standard parts such as shaped links and connecting lugs on end hinges. They may have a different shape depending on the model of the bracelet, but their main functions remain the same. An important element of the bracelet is also a lock, which ensures its secure fastening on the wrist. The safety clasp is a popular option that provides ease of use and secure wearing of the bracelet. Making bracelets is not only a process of creating jewelry, but also an opportunity to show your individuality and creativity. Each bracelet is unique and can become a bright accent in the image of its owner. Therefore, it is important to approach the manufacturing process with love and attention so that each bracelet is a real work of art. Glider bracelet is a unique piece of jewelry that you can make yourself. In the process of creating soft and hard bracelets of this type, the same techniques and materials are used. To make the links of a glider bracelet, you need to have shaped links and connecting lugs. To begin with, a square bar is taken and it is rolled until a rectangular bar is obtained. This bar is then cut into two identical pieces, which are then folded together and tied at one end. The length of the bonded end is approximately 15-20 mm. To complete this step, the soldered end is filed into a spitz to make it easier to pull it into the spinneret. The next step is to create the gliders and connecting lugs. For this, a semicircular wire is used, which can be obtained after drawing and expanding two bars soldered at one end. It is from this wire that gliders and connecting lugs are made - important elements of a glider bracelet. Thus, the process of manufacturing a glider bracelet requires a special laboriousness. Thanks to the skillful use of various techniques and materials by the jeweler, each glider bracelet becomes special and original in its own way. For the manufacture of gliders, semi-circular wire is drawn and then annealed to give it the desired softness and flexibility. After that, the wire is bleached and wound into a spiral on a steel crossbar, pre-wrapped with tape paper. To remove the paper, the spiral with the crossbar is subjected to firing, as a result of which the paper burns out and the spiral is easily removed from the crossbar. Further, the resulting spiral is installed in a special wooden block, which is designed to cut the spiral into links. Using a jigsaw, the spiral is cut and links are obtained, which are called gliders. In order for the gliders to be firmly connected, they are joined in a fugue and soldered. After that, the gliders are straightened on a special frame to give them the correct shape. Then the gliders are put back on the crossbar in order to continue the subsequent processing steps. After refitting the bolt, the links are filed at the solder points to remove excess material and give the gliders their final look. And now, the sliders are ready to use. To create shaped internal links, the wire must be selected with the required section and wound onto a spiral to get links. However, in addition to this method, the shaped link can be 117

formed from sheet metal. A figured link is manually stamped from the received links. Then the link is formed, joined in a fugue and soldered. After that, it is straightened on a special mandrel. And the last step is to put the links in different directions with a fugue on the crossbar on which the spiral was wound, as well as filing the links at the soldering points. The whole process requires accuracy and attention to detail in order to obtain high-quality and durable links. To assemble the bracelet, you need to take two gliders and install a shaped link between them. For reliable connection of gliders and shaped links, connecting lugs of round or semicircular section are used, which are made in the same way as gliders. After manufacturing, the lugs are etched for 4-5 minutes to oxidize and bake to avoid soldering with other elements of the bracelet during assembly. In addition, connecting lugs are installed between the gliders and shaped links, through which the connecting pin passes. This allows you to create a strong and reliable connection between the elements of the bracelet. For additional stability and to prevent the product from falling apart, the link is connected with a special wire. After assembling half of the bracelet, a hinge is soldered to the end link. Then all the pins are soldered and filed at the place of soldering to ensure the perfect appearance and reliability of the connection of the bracelet elements. Thus, the entire process of assembling the bracelet is carried out with special attention to detail and the quality of the connections in order to obtain a beautiful and durable piece of jewelry. The assembly of the bracelet begins with the taking of two gliders, which can be a different number depending on the design. Then a shaped link is installed between the gliders, which gives the bracelet a special shape. To ensure the strength and reliability of the connection, connecting lugs are added between the gliders and shaped links, through which the connecting pin is pulled. To prevent the product from falling apart, the link is connected with a special wire that securely fixes all the elements. Thus, the first half of the bracelet is created. A hinge is soldered to the end link, which allows the bracelet to flexibly adjust to the arm. Then all the pins are soldered and neatly filed at the place of soldering, so that the product looks neat and safe to use. It is through such a complex and meticulous process that the beautiful and elegant links of the bracelets are created. It is important to take into account every detail and ensure a strong connection so that the bracelet is not only a stylish decoration, but also a durable accessory. The need for care and professionalism in the manufacture of bracelets highlights the importance of craftsmanship and meticulous work in the jewelry industry. Plain shank, also known as flat shank, is the most popular type of shank. They are widely used as wedding rings. However, when choosing a smooth ring, it is necessary to take into account not only its width, thickness and size, but also the section profile. Each of these parameters affects the appearance and comfort of wearing the ring. In addition to flat rings, there are also round and segment models. Round rings have a classic shape and are often chosen for everyday use. Segment rings, on the other hand, have a more unusual shape made up of segments, which creates an interesting and stylish look. The thickness of the rings may vary depending on their type. Flat rings are usually about 0.8 mm thick, while segmented rings can be up to 3 mm thick. This parameter also affects the strength and durability of the product. Ring width is another important aspect when choosing rings. It depends on the preferences of the customer and can vary from narrow models to wide options. The width of the rings also affects their appearance and wearing comfort. 118

Finally, the size of the rings is one of the key factors when ordering a product. The size is determined by the size of the finger on which the ring will be worn. There is a wide range of sizes ranging from 15.0 to 24.0 mm in 0.5 mm increments. This ensures that the ideal size can be selected for each customer. Shank making is a complex process that requires precision and attention to detail. First, the master creates a drawing of the shank to determine all the necessary dimensions. Then he chooses the size of the ring, its thickness and width. But the most important step is to calculate the length of the workpiece in order to get the perfect ring. To calculate the length of the workpiece, special tables are used that already contain precalculated values. These tables are based on a formula that takes into account the inner diameter and thickness of the shank. For example, to calculate the length of the workpiece, the formula Dext = Dint + 2h is used, where Dext is the outer diameter, Dint is the inner diameter, h is the thickness of the shank. Thus, the process of making a shank requires not only skill and experience, but also mathematical calculations. It is important that each ring fits its owner perfectly, so every detail must be made with the highest precision and attention to detail. The calculation of the size of the square in the manufacture of the ring has its own characteristics. After determining the length of the workpiece, the material is selected - gold, silver, cupronickel or copper. Then the bar is rolled in profile rolls until a square section with a side equal to the width of the ring is obtained. However, when determining the dimensions of the square, it is necessary to take into account the broadening of the workpiece during flat rolling, which is approximately 10% of the width. This broadening depends on the amount of compression by the rolls and the number of passes. Therefore, in order to obtain the ideal profile of the finished product, it is important to take this factor into account when calculating the dimensions of the square. For this, various methods can be used, for example, longitudinal rolling of the workpiece in flat rolls or passing it through a segment pass. Thus, the correct calculation and choice of method will achieve the desired result and create a high quality ring. To obtain an annular shape of the workpiece during longitudinal rolling in flat rolls with side stops, it is necessary to select the size of the workpiece in such a way that the pass can be filled completely in one pass. However, if it is required to obtain a segmented section of the shank, then an additional intermediate annealing must be carried out to prevent the occurrence of cracks and other defects. After rolling, the length of the future shank is marked on the resulting workpiece. However, when cutting the workpiece 1 mm more than the marked length, a margin is left for subsequent sawing and leveling. This is necessary in order to accurately form the segmental section of the shank and ensure its correct shape. To ensure high-quality and accurate rolling of the workpiece in flat rolls, it is important to choose the right dimensions and parameters of the caliber. It is also necessary to take into account the possibility of intermediate annealing in order to avoid the occurrence of cracks and defects during the formation of the bar. In addition, when parting off the workpiece, a small margin should be left for subsequent processing and alignment in order to achieve the required accuracy and shape of the segmental section. To achieve the accuracy and quality of the final product, it is important to carry out the filing step using coarse or medium files, ensuring a right angle between the sides of the workpiece.

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The tires of the large ring can be bent using tire pliers for a smooth rounding. This allows you to get an even seam. The cutting angle will depend on the thickness of the rolled product and the size of the ring, and can range from 15 to 30 degrees. If the workpiece is soft, then bending can be done using pliers with jaws rounded from the inside. And for bending difficult-to-give workpieces, you can use a crossbar or flakeisen grooves. The sawing step is an integral part of the product manufacturing process and plays a key role in achieving the desired shape and precision. The final quality and strength of the product depends on the correct sawing. Therefore, it is important to devote sufficient time and attention to this stage in order to ensure high accuracy and reliability of the final product. Before starting the soldering of the ring, it is necessary to carry out a number of preparatory procedures. First, the ring must be spliced to ensure a very snug fit and no gaps. Then, solder is cut into the ring and the whole shank is fluxed. This is necessary to ensure reliable welding and avoid corroding the walls of the ring during soldering. After that, the workpiece is bent into a ring and adjusted to a perfect fit. This is done by jointing the workpiece to eliminate any gaps. Then, moving the workpiece across the groove, the entire workpiece is bent into a ring by hammer blows on the crossbar to create the required shape. After that, the ends are jointed to exclude the possibility of damage to the ring at the point of the joint during soldering. This is very important, otherwise the solder can corrode the walls of the ring and cause the seam to break or leave a noticeable solder streak on the finished product. It is important to note that carrying out all these preparatory procedures before soldering the ring is a key moment in the process of manufacturing a quality product. The strength and durability of the welded joint depends on the correct implementation of these steps. Therefore, it is necessary to pay special attention to each stage and ensure maximum accuracy and quality of work. To achieve a strong and reliable connection, it is important to carry out the soldering process correctly. To begin with, you need to warm up the tavern to a certain temperature, preferably to cherry color. This ensures successful soldering. After this, when starting soldering, you need to ensure that the junction becomes crimson. Thus, we can be sure of the quality and reliability of the connection. However, in addition to the correct temperature, it is also important to consider the correct amount of solder. You need to take enough solder so that it completely fills the seam, but at the same time does not spread over the surface. Only by observing all these factors can you achieve the desired result and create a strong connection. Before starting the soldering process, you need to make sure the quality of the connection. After soldering is complete, cool the ring. Then the procedures of bleaching, washing and drying of the ring are carried out, as well as an examination for possible defects. If no defects are found, you can proceed to the next step - putting the ring on the crossbar and start editing. For this, a hammer is used, which is struck on the entire surface of the ring. This process continues until the inner side of the ring is completely attached to the thickened side of the crossbar. However, it is important to remember that when editing, you must be very careful not to damage the ring itself or the bolt. Also, before fitting the ring on the bolt, it is recommended to apply a special lubricant to facilitate the process and reduce friction. After finishing, it is necessary to re-examine the ring for defects and make sure that it fits perfectly. If everything is done correctly, then you can be sure of the quality of the connection and continue working with it. A perfect connection and quality of work can only be guaranteed when all sides of the ring are straightened. The filing process starts from the inside and gradually moves to the sides, and then the outside is filed. To perform this operation, various tools are used, such as needle files and files. 120

After the filing step, the ring goes through a scraping process, as a result of which the chamfer is removed from the inner edge. This is followed by a polishing step, which gives the ring a smooth surface and a pleasant sheen. It is important to note that scraping and polishing is an integral part of the ring processing process and allows you to achieve the best results. Depending on the task at hand, there are various methods for processing taverns, in addition to the steps already mentioned. For example, to remove deeper defects or correct the shape, specialists can use specialized machines and tools. This allows you to achieve more precise processing and get the perfect shape of the shank. In addition, heat treatment techniques are often used to increase the strength and durability of the shank. This process improves the mechanical properties of the material and makes the shredder more resistant to stress. Also, to improve the performance of the shank, you can apply a coating of a special material. This helps protect the shank from environmental influences and improve its appearance. All these methods of processing tires require high precision and experience on the part of specialists. Only with the correct application of these methods, it is possible to achieve high quality and bring the product to an ideal look. It is important to note that each step of the shank processing plays a role in obtaining the ideal result, and their consistent application is the key to a successful processing process.

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Conclusion Jewelry art was one of the most significant aspects of life in Bukhara in the 19th century. It reflected the desire of society for luxury and wealth, which found its manifestation in the work of local jewelers in the central market of the city - Toki Zargaron or “jewelers’ dome”. According to available data, there were about 400 jewelers in Bukhara at that time, which made the city the largest school of jewelry crafts and significantly influenced craftsmen from other regions. The high level of craftsmanship and rich cultural heritage, which continue to inspire and delight us to this day, make Bukhara not only a commercial and cultural center, but also a place for the creation of unique and beautiful works of art. This clearly demonstrates the importance of art in society and its influence on development and progress. The art of the cities of the Muslim East, including Bukhara, developed and underwent transformations over time, but retained a single style based on Islamic ideas of beauty. This style sought to maximize the idealization of form, emphasizing the sophistication of lines, and found its most striking embodiment in jewelry. Jewelry in this style was distinguished by its particularly elegant shapes and details. The richness of pendants and loose connections gave the products sophistication and lightness. Craftsmen used filigree, openwork cuts and graining to add a touch of luxury to jewelry. They also skillfully combined semi-precious stones - amethysts, beryls, tourmalines and corals, creating unique and attractive compositions. Jewelry art in the cities of the Muslim East, including Bukhara, was one of the manifestations of the general aesthetic approach of the Islamic world. These exquisite pieces of jewelry were not only symbols of status and wealth, but also embodied the deep ideals of beauty and harmony inherent in Islamic culture. The artistic significance of Bukhara jewelry is deeply connected with their ancient ideas, which emphasizes their traditionality and uniqueness. Having stable forms, they help convey their original meaning. It is important to understand that to become a true master jeweler, you must have not only skill, but also deep attention to detail. All who strive for excellence in this art must be obsessed with developing and unlocking its potential. However, despite the importance of jewelry schools, they cannot teach a master how to become a real jewelry artist. This is a skill that we must develop solely through our own efforts and dedication. Such ideas came to the author's mind very early and helped him at the very beginning of his craft. He realized that jewelry making is not only a craft, but also an art. His goal was to revive the art and traditions of jewelry making of his ancestors and pass on this skill to future generations. He sought to ensure that the cultural heritage of his country and people did not disappear over time, but was reflected in all its greatness. Mamur Fataev constantly developed, improved and practiced, and the results of his efforts exceeded all expectations. Not only did he become an excellent jeweler, he studied all aspects of jewelry art from a practical and theoretical point of view. Now the master shares his knowledge with those who want to continue the legacy of their ancestors.

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Annotated bibliography 1. Abdullaev T., Fakhreddinova D., Khakimov A. Song about Metal. T.: Izd. of literature and art named after G. Gulyam, 1986. 2. Ailova G.N., Vasilieva M.P., Petrenko I.A., Ryzhenko G.N. Commodity management and expertise of metal and jewelry goods. Moscow 2005, 304 p. 3. Noble metals and their application. Institute of Physics Institute of Physics of Metals, Academy of Sciences of the USSR. / Under the editorship of Academician Sadovsky V.D.-. Sverdlovsk, 1971. - 288 p. 4. Brepol E. "Theory and practice of jewelry making". М., 2000. 5. Boravsky V. A. Useful Pages for the Master. M.: SOLON-R Publishing House, 1999. - 207 p. 6. Bukanov V.V. "Colored stones". Spb., 2008. 7. Ivanov V. N., Kazennov S. A., Kurchman B. S. et al.; under the general ed. Shklennik Ya. I. I., Ozerov V. A. Casting on investment models. М.: Mashinostroenie, 1984. - 408 p., ill. 8. I.H. Khalilov, M.I. Khalilov Jewelry Casting S. 2001- 457 p. 9. Lawrence, Kallenberg. Modeling in wax for jewelers and sculptors. M., 2004- 367 p. 10. Kambarova O.S. Jeweler's Arts of Uzbekistan - Tashkent, 2000. 11. Kornilov N.I., Solodova Y.P. Jewelry stones. - Moscow: Nedra, 2007. 282 p. 12. Crowe, D. Handbook for jewelers / D. Crowe. - Moscow: Art-Rodnik, 2018. - 836 p. 13. McCright, Tim. Practical Casting. Manual for workshop. М. 2002 14. Maximikhin B. A. Brazing of metals in instrument-making. L.: Printing House No. 12 of Lensovnarkhoz, 1959. - 114 p. 15. Malyshev, V.M. Silver / V.M. Malyshev, D.V. Rumyantsev. - Moscow: Metallurgy, 2021. 312 p. 16.Maria Jose Forcadel Berenger, Jose Asuncion Pastor. Drawing for jewelers: Per. s spanish. Moscow: "ART-RODNIK" Publishing House, 2005. - 192 p., ill. 17. Marchenkov V.I. Jeweler's business. М., 1990 18. Oldershaw, K. Precious stones / K. Oldershaw. - Moscow: Martin, 2018. - 412 p. 19. Prostakov S.V. Jeweler's business. - Rostov-on-Don: Phoenix, 2009. 20. Sazonova M.V. Decorations of the Uzbeks of Khorezm. In the book "Traditional Culture of the Peoples of West and Central Asia". Collection of the MAE, XXVI. Л.,1970 21. Skurlov, V. Faberge and Russian court jewelers / V. Skurlov, G. Smorodinova. - Moscow: TERRA-Book Club, 2020. - 336 p. 22. Fakhretdinova, Delyara Akhatovna. Jewelry art of Uzbekistan / D. A. Fakhretdinova. Tashkent: Izd. of Literature and Art, 1988. - 204 с.: ill. 23.https://cyberleninka.ru/article/n/yuvelirnoe-iskusstvo-v-uzbekistane-istoriya-isovremennost/viewer 24. https://academicsresearch.ru/index.php/MSRISJ/article/view/1744 25. https://elibrary.ru/item.asp?edn=lgffwi&ysclid=lq30gqxeqg405652368 123

Contents: 1.PREFACE:History of Bukhara Jewelry Art: A Tapestry of Influences I. Jewelry craftsmanship - Harmony of Inner and Outer Beauty II. Pure metals, non-precious alloys III. Treasures of Uzbekistan: 19th Century Jewelry Art IV. Classification of jewelry stones V. Auxiliary materials VI. Basic technological operations for making jewelry by hand VII. Mechanisms used in jewelry VIII. Jewelry production technologies. Basic moments IX. Filigree or the technique of the finest patterns X. Surface treatment of jewelry castings XI. Defects in jewelry castings and their elimination XII. Production of individual jewelry Conclusion Annotated bibliography

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