topaz (mineral)

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Scope note
An aluminum silicate containing fluorine that is formed by fluorine-bearing vapours given off during the last stages of the crystallization of igneous rocks. The topaz that is valued as a gemstone occurs in prismatic crystals that are transparent and lustrous, of white (colorless), yellow, brown, pale blue, pink, red, or pale green color, found in Brazil, Mexico, Saxony, Scotland, Japan, the Ural Mountains, and elsewhere. Colorless topaz may be mistaken for diamond when brilliant cut. Colored topaz may be unstable and bleached by sunlight. It is believed that the topaz identified by modern mineralogists was unknown to ancient Greece and Rome and the writers of the Old Testament; the stone called "topazos" by the ancients was probably the minerals chrysolite, peridot, or yellow sapphire.
topaz
Accepted term: 29-Apr-2024