Abstract

There are three types of gemstone materials as defined by the U.S. Federal Trade Commission: natural gemstones are found in nature and at most are enhanced; imitation or simulated, fake, faux, etc, material resembles the natural material in appearance only and is frequently only colored glass or even plastic; and synthetic material is the exact duplicate of the natural material, having the same chemical composition, optical properties, etc, as the natural, but made in the laboratory. The word gem cannot be used for synthetic gemstone material. The synthetic equivalent of a natural material may be used as an imitation of another. Synthetic gemstone materials often have multiple uses. Synthetic ruby and colorless sapphire are used for watch bearings, unscratchable watch crystals, and bar-code reader windows. Synthetic quartz oscillators are used for precision timekeeping, citizen's band radio (CB) crystals, and filters. Synthetic ruby, emerald, and garnets are used for masers and lasers. In the gemstone jewelry market, synthetics provide a less expensive alternative to natural gemstones, but of a better quality than that available in costume jewelry. In general, a synthetic should be available for no more than 10% of the cost of equivalent-quality natural gemstone to be commercially viable. The important properties are those of importance in natural gemstones. Several gemstone species occur in various colors, depending on the presence of impurities or irradiation-induced color centers.

The most frequently used techniques for the commercial manufacture of synthetic gemstone materials are based on crystal growth from the meet or crystal growth from solution.