Definition for TO'PAZ

TO'PAZ, n. [Gr. τοπαζιον.]

A mineral, said to be so called from Topazos, a small isle in the Arabic gulf, where the Romans obtained a stone which they called by this name, but which is the chrysolite of the moderns. The lustre of the topaz is vitreous; the streak white; the color yellow, white, green, blue, pale; transparent, or subtranslucent; fracture subcoinchoidal, uneven. Its ultimate composition is silicum, aluminum, fluorine, oxygen. The primary form of its crystal is a right rhombic prism. It has been supposed to be a fluosilicate of alumina. Topaz is valued as a gem or precious stone, and is used in jewelry.

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