What is a Gemstone?

By modern definition, a gemstone is a mineral or other natural material that is beautiful enough, durable enough, and rare enough, to be used for personal adornment or for the embellishment of personal possessions.

Most gemstones are rather rare minerals. They are naturally occurring inorganic crystalline elements or compounds that have chemical compositions and physical properties that are fixed or may vary between very fixed limits. Gemstones display the desirable attributes of beauty, rarity, and durability.

Other materials, that are less commonly used for gem purposes include:

• rocks, that are formed from mixtures of minerals e.g. lapis lazuli.
• non crystalline materials e.g. amorphous opal.
• ornamental materials (ornamentals) that are those minerals which due to their lack of transparency owe their beauty to their body colour and/or attractive pattern of colours e.g. malachite.
• Biological (organic) gem materials, which are materials produced by living organisms e.g. ivory, amber, or precious coral.

With respect to gemstones:

1. Most are single minerals, and not other materials.
2. Of the more than 3,000 known minerals found in the earth, the gem minerals total about 100.
3. Gem minerals are very minor constituents of the 'living planet' known as planet Earth.

Today many gemstones are being value-enhanced by the application of various treatments to the gemstone or gemstone rough. Although the original materials may have a natural origin, man’s intervention has converted these materials into value-enhanced gemstones e.g. heat treated ruby and sapphire, ‘oiled’ emerald, irradiated coloured diamond, diffusion-coated sapphire.

In contrast, synthetics and imitations can not be described as gemstones; for essentially they are man-made. Therefore:

• A synthetic or artificial gemstone is a man-made material having a chemical composition, crystal structure, and physical properties that are identical to those of a (natural) gemstone. e.g. synthetic sapphire, synthetic diamond.
• Imitations are man-made (manufactured) products that only visually resemble the gemstone they are intended to simulate. e.g. glass, plastic, composite stones which are made from several components.

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