Definitions for: Tridymite

[n] a mineral form of silica

Webster (1913) Definition: Trid"y*mite, n. [Gr. ? threefold. So called in
allusion to the supposed threefold nature of the twin
crystals.] (Min.)
Pure silica, like quartz, but crystallizing in hexagonal
tables. It is found in trachyte and similar rocks.

See Also: mineral, silica, silicon dioxide, silicon oxide