Occurs massive; brittle; breaking with high lustre like hardened tar, and with curved surface; melts and burns readily with flame and smoke; gravity 1.2, sometimes floats on water.
Value.—Used for cements and varnishes.
Localities.—Found generally near the surface. Near the coast of Santa Barbara, Cal.; West Virginia, twenty miles south of Parkersburg.
8.—Azurite.
Occurs in crystals and masses with glassy lustre, or earthy and dull; brittle; crackles and blackens, and finally fuses by heat; dissolves with effervescence in nitric acid; gravity 3.5.
Value.—A valuable ore of copper, containing sixty per cent.
Localities.—Found chiefly in lead and copper mines. Perkiomen lead mine, Cornwall, Phoenixville and Nicholson’s Gap, Pa; near New Brunswick, N. J.; near Mineral Point, Wis.; Polk County, Tenn.; Calaveras and Mariposa Counties, Cal.; near Virginia City, Mont.
9.—Baryta, or Heavy Spar.
Occurs in crystals, plates and masses; powder white; brittle; crackles when strongly heated; not dissolved in acids; easily distinguished by its weight; gravity 4.5, or twice as heavy as Gypsum.
Value.—Used extensively as white paint and in pottery.