Celestite
Katsepy, Madagascar

This specimen measures 18cm x 15cm


Celestite     SrSO4

Sulfate; strontium sulfate, sometimes with much barium

Color and Luster: White, colorless, bluish, reddish; vitreous, pearly; streak white

Hardness: 3-3.5

Cleavage: Perfect in one direction, good in a second, and distinct in a third

Fracture: Uneven, brittle

Crystals: Orthorhombic; usually thin to thick tabular crystals; also fibrous, cleavage masses, nodular; rarely granular or lamellar

Photo by Mary Sutherland


Descriptions taken from
The Audubon Society Field Guide to North American Rocks and Minerals