tridymite

/trid-uh-mahyt/US // ˈtrɪd əˌmaɪt //

三晶石,三聚氰胺,三角石,三角形石

Definitions

n.名词 noun

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

The crystals, called cristobalite and tridymite, swim in clouds around stars just before they begin to form planets.
When crystalline grains or blebs of quartz occur, we have a quartz-trachyte; when tridymite is abundant, as in the trachyte of Co.
Spherulites may be regarded as radiate aggregates of such microliths (mostly felspar mixed with quartz or tridymite).