brewsterite

Century Dictionary and Cyclopedia

1. n. A white, yellow, or green pellucid mineral of the zeolite family, occurring in short prismatic crystals; a hydrous silicate of aluminium, strontium, and barium.

Wiktionary

1. n. mineralogy Any of a series of hydrothermal tectosilicate minerals of the zeolite group.

GNU Webster's 1913

1. n. A rare zeolitic mineral occurring in white monoclinic crystals with pearly luster. It is a hydrous silicate of aluminia, baryta, and strontia.