tridymite

[ trid-uh-mahyt ]

noun

, Mineralogy.

1. a polymorph of quartz occurring in the form of small crystals, commonly twinned, in siliceous volcanic rocks.

Word History and Origins

Origin of tridymite¹

1865–70; < German Tridymit, equivalent to tridym- ( Greek trídym ( os ) triple, equivalent to tri- tri- + ( dí ) dymos didymous ) + -it -ite ¹

Example Sentences

The crystals, called cristobalite and tridymite, swim in clouds around stars just before they begin to form planets.

From The Daily Beast

When crystalline grains or blebs of quartz occur, we have a quartz-trachyte; when tridymite is abundant, as in the trachyte of Co.

From Project Gutenberg

Spherulites may be regarded as radiate aggregates of such microliths (mostly felspar mixed with quartz or tridymite).

From Project Gutenberg