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In addition, it must be hard and durable. Its value increases if it is also rare.The beauty of a gem is measured in terms of its clarity, brilliance, and color. Comments
A mineral species has to possess these five characteristics... Minerals are solid, naturally occurring, inorganic compounds that possess an orderly internal structure and a regular chemical composition. A mineral species has to possess these five characteristics to be regarded as scientifically valid. The first and most basic characteristic of all minerals is that they occur naturally.