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Techniques Gold-: In order to understand the range of gold-and silverwork—it extends from works of high art to merely utilitarian objects—it is necessary to examine the uses of gold and silver and the techniques gold- of shaping them.
Uses. Objects of gold and silver can be broadly divided into four classes. The first comprises personal ornaments, ranging from the heavy gold torques of the preclassical age to modern wedding rings.
The fineness of gold is expressed in terms of the carat, a term derived from the Arabic qirdt, a weight of 4 grains. The carat is a single part of a standard of 24 parts. Twenty-four carat gold is pure gold; 18 carat gold is 18 parts gold, 6 parts alloy.
techniques gold- of Shaping. One of the classic techniques of the goldsmith—the term is to be understood as including the silversmith—is raising. Raising is the shaping of a hollow vessel from a single circular sheet of metal without a join.
Ores from veins or lodes are generally obtained with large quantities of gangue material, and crushers and ball or rod mills are used to break down the ore into a fine enough condition to free the gold. The gold, which is very heavy, is then separated from the lighter gangue materials by techniques gold-, such as vibrating tables or jigs, which utilize the differences in density. Further separation of the gold usually involves amalgamation, cyaniding, or flotation processes. |
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