Underground Treasures: How and Where to Find Them / A Key for the Ready Determination of All the Useful Minerals Within the United States

by James Orton

36.—Gypsum.

Occurs in plates, fibres coarse and fine, and massive; pearly or glistening; powder white, which if heated and mixed with water, turns hard; does not dissolve in sulphuric acid; may be scratched by the nail; gravity 2.3.

Value.—Used for stucco, manure, glazing, statuary, manufacture of glass, etc. A variety, called Satin Spar, worked into necklace beads and other ornaments, is finely fibrous and compact, taking a polish (though easily scratched,) and then resembles pearl or opal.

Localities.—Found with marl or clay, limestone and salt. Camillus, Manlius, Stark and Lockport, N. Y.; on the St. Mary’s and Patuxent, Md.; Washington County and Lynchburg, Va.; Charleston, S. C.; Poland, Ottawa and Canfield, O.; Davidson and Summer Counties, Tenn.; Grand Rapids and Sagenaw Bay, Mich.; Des Moines River, Iowa; Walker Lake and Six Mile Cañon, Nev.; Fort Dodge.