D defs.my
Entry 1 sense Webster, 1913

Tridymite

· Trid·y·mite · IPA
01 n. Pure silica, like quartz, but crystallizing in hexagonal tables. It is found in trachyte and similar rocks.
  1. 1.
    Pure silica, like quartz, but crystallizing in hexagonal tables. It is found in trachyte and similar rocks.(Min.)