18.—Celestine.
Occurs crystallized, fibrous and massive; color white, often faint bluish; glassy lustre; very brittle; under the blow-pipe crackles and melts, tinging the flame red; does not dissolve in acids; gravity 4.
Value.—The source of nitrate of strontia, used in fire-works.
Localities.—Found in limestone, gypsum and sandstone. Rossie, Schoharie, Chaumont Bay, Depauville and Stark, N. Y.; Frankstown, Pa.; Strontian and Put-in-Bay Islands, Lake Erie; near Nashville, Tenn.; Fort Dodge, Iowa.