Precious and Semiprecious Stones

Abstract

Gems are found worldwide. When there is a sufficient quantity to be worked, it is termed a deposit. A deposit, as well as the location of discovery of a single find, is termed the gem occurrence. The gem cut defines the shape of a stone and determines whether it sparkles or shines. The cut of a gem is often the first consideration in choosing the proper setting for the stone. In addition to gemstone cutting, over the centuries countless other methods have been developed to improve upon the natural properties of gemstones. These techniques are known as enhancements. Synthetic gems have been manufactured since the 1960s as an attempt to substitute for naturally occurring gems. Advances in the methods of manufacture have made it possible to produce synthetic gems of equal or better appearance than naturally occurring gems. Thus these important aspects of gemstones—properties, cuts, enhancements, and synthetic gem preparation—are to be discussed in this chapter.