Jewelry21/09/2021 Off By riometadmin
Jewelry, objects of personal adornment prized for the craftsmanship going into their creation and generally for the value of their components as well. Throughout the centuries and from culture to culture, the materials considered rare and beautiful have ranged from shells, bones, pebbles, tusks, claws, and wood to so-called precious metals, precious and semiprecious stones, pearls, corals, enamels, vitreous pastes, and ceramics. In certain eras, artist-craftsman have sometimes placed less emphasis on the intrinsic value of materials than on their aesthetic function as components contributing to the effect of the whole. Thus, they might fashion a brooch out of steel or plastic rather than gold or platinum. Furthermore, in addition to its decorative function, during much of its history jewelry has also been worn as a sign of social rank—forbidden by sumptuary laws to all but the ruling classes—and as a talisman to avert evil and bring good luck. During the Middle Ages, for example, a ruby ring was thought to bring its owner lands and titles, to bestow virtue, to protect against seduction, and to prevent effervescence in water—but only if worn on the left hand.
Materials and methods:
The first materials used to make objects for personal adornment were taken from the animal and vegetable world. The material taken from the animal world, in a natural or processed form, constituted the actual adornment, whereas vegetable fibers served as its support. A great variety of shells and pieces of shell were used during the prehistoric age and are still used in the certain island and coastal cultures to make necklaces, bracelets, pendants, and headdresses. In the inland regions, the first materials used for personal adornment came from mammoths’ tusks, the horns of reindeer and other animals, and, later on, amber and lignite. All materials that have been used over the centuries for the manufacture of jewelry have undergone to some extent mechanical, physical, or chemical treatment for the purpose of transforming their raw shapes into shapes that, in addition to being functional, also satisfy certain aesthetic concepts.
Precious metals and their properties:
Of gold’s properties, when it was first discovered (probably in Mesopotamia before 3000 BCE), it was the metal’s malleability that was a new phenomenon: the only beeswax, when heated to a certain temperature, could be compared to it. Gold’s molecules move and change position in accordance with the stresses to which it is submitted, so that when it is beaten it gains in the surface area what it loses in thickness. In modern jewelry, gold can take on a variety of hues when it is alloyed with other metals: water green, white, grey, red, and blue.
After gold, silver is the metal most widely used in jewelry and the most malleable. Although known during the Copper Age, silver made only rare appearances in jewelry before the Classical Age. In general, silver was, and still is, used in jewelry for economic reasons or to obtain chromatic effects. It was often used in the 17th, 18th, and 19th centuries, however, as support in settings for diamonds and other transparent precious stones, in order to encourage the reflection of light.
Another rare metal, whose use in jewelry is fairly recent, is platinum. From the 19th century onward this metal was used ever more frequently in jewelry because of its white brilliance and malleability, as well as its resistance to acids and its high melting point.
Modern jewelry, such as that designed by early 20th-century artists, introduced nonprecious metals such as steel.
The basic components of jewelry have always consisted of sheet metal, metal cast in a mold, and wire (more or less heavy or fine). These components take on the desired shape by means of techniques carried out with the help of tools. Gold in its natural state was beaten while hot or cold and reduced to extremely thin sheets (this operation could be performed with stone hammers). The sheets were then cut into the desired sizes.
Examination of the most ancient pieces of jewelry shows that one of the techniques used most widely in decorating metal sheets for jewelry was embossing (relief work). Throughout the centuries embossing techniques have remained substantially unchanged, although in modern times mechanization has made possible mass production of decorative parts of jewelry, with great savings of time and labor but with a corresponding lack of art.
In repoussé the relief is pressed (in a negative mold) or hammered out from the reverse side of the gold sheet and then finished off on the right side with a hammer or engraving tool. For half-modeled or completely round reliefs, the gold leaf was pressed onto wooden or bronze models. Completely round objects were made in two pieces and then welded together.
In addition to gold, silver, and platinum, the precious materials most widely used in jewelry are gems-any precious or semiprecious stone. By definition, this group also includes some animal and vegetable products with precious characteristics, such as amber, pearls, and coral. Conventionally, the following are classified as precious stones: diamonds, rubies (corundum), emeralds (beryl), and sapphires (corundum). To these, however, can be added chrysoberyl, topaz, and zircon because of their hardness and their refraction and transparency index.