Localities.—Found in limestone and gypsum, and around geysers and sulphur springs. Springport, N. Y.; on the Potomac, twenty-five miles above Washington; Put-in-Bay Island, Lake Erie; Clear Lake, Cal.; Santa Barbara County, Col.; Humboldt County, Nev.
72.—Tin Ore.
Occurs in crystals, grains and masses; high lustre; powder gray or brownish; brittle; will strike fire with steel; unaltered by heat or acids; gravity 7,—being nearly as heavy as lead-ore.
Value.—The only ore of tin, containing seventy-nine per cent. No gold-mine ever paid such profits as the tin mines of Cornwall.
Localities.—Jackson, N. H.; Temescal, Cal.; Boonville, Idaho; near Fredericktown, Mo.
73.—Topaz.
Occurs in crystals; glassy lustre; brittle; scratches rock-crystal; not acted upon by ordinary heat or acids; gravity 3.5.
Value.—A gem; the most esteemed are the rose-red and white.
Localities.—Found in granite. Trumbull, Willimantic and Middletown, Conn.; Crowder’s Mountain, N. C.; Thomas’s Mountains, Utah.