One of the oldest imitation-substitutes is glass..

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Man-Made Gems

The creation o( gems in the laboratory has been a goal of scientists a entrepreneurs for many years. Today most of the popular gemstones can be synthesized, that is, manufactured in a laboratory or factory from chemical raw materials.

It is important to distinguish between synthetics and imitations. An imitation is a material that has some of the desirable characteristics of a more costly material. A synthetic is a man-made duplication of a naturally. ally occurring substance.

One of the oldest imitation-substitutes is glass. Class has h( manufactured for thousands of years. Glassmaking was considered great art by the ancient Egyptians, and Greek and Roman jewelry studded with glass replicas of gems can be seen in museums. Even today glass is a widely used and popular substitute for colored gems such ruby, emerald, and amethyst, and it can sometimes be effective a attractive. Frequently glass stones are set with a backing of metallic to The foil reflects light and creates a far greater brilliance than the glass alone could achieve. But glass lacks the hardness and dispersion many natural gemstones, and man has long sought better gem substitutes.

Man-Made Gems

One by one, during the past hundred years, each of the major gems has been manufactured in the laboratory. The first to appear were ruby and sapphire, followed by spinel, emerald, diamond, opal, turquoise ¬and Chrysoberyl. These synthetic gems are optically and chemic,3 identical with their natural counterparts. For example, natural ruby aluminum oxide, colored red by chromium, that crystallizes in for with hexagonal symmetry. Synthetic ruby is usually made by melting aluminum oxide that contains a trace of chromium.

The resulting crystal has the same internal atomic structure as natural ruby, as well as the same optical properties, hardness, and chemical composition. In fact, the only significant difference between this material and natural ruby the place of origin: a laboratory rather than deep within the earth Fortunately for the gem trade, there are ways to distinguish between natural and synthetic gems.

These are based chiefly on tell-tale intern, markings. In natural gems there are frequently distinctive inclusion either gas bubbles, liquid inclusions, or crystals of other minerals. I synthetics we find round bubbles, curved growth lines, and various other markings that reveal the manufactured origin.

In recent years technological developments in the areas of semiconductors and lasers have required the development of new and special crystals with useful optical or electronic properties. Some , 132 these are brightly colored or have other characteristics suitable for gem use. These new synthetic gems have no natural counterparts. They are unique laboratory creations that have extended the world of gemstones in new and unique directions.


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