Aluminum silicate mineral, AlSiO(F,OH), that is valued as a gemstone. It is formed by fluorine-bearing vapours given off during the last stages of the crystallization of igneous rocks. Pure topaz may be colourless and, when brilliant-cut, has been mistaken for diamond. It may also be various shades of yellow, blue, or brown. Imperial topaz, with vivid reddish orange colour, from Minas Gerais, Braz., is very highly valued.
Topaz from Minas Gerais state, Brazil—Lee Boltin
This entry comes from Encyclopædia Britannica Concise.
For the full entry on topaz, visit Britannica.com.
Seen & Heard
What made you look up topaz? Please tell us what you were reading, watching or discussing that led you here.