THE GEMS--PRECIOUS METALS--VALUABLE ORES AND USEFUL MINERALS OF THE UNITED STATES FROM AGATE TO ZINC--THEIR DISTINGUISHING CHARACTERS, USES AND LOCALITIES--A MINERALOGY FOR MINERS. 1.--AGATE. This stone is a mixture of several kinds of quartz, mainly the white, red, brown and black, disposed in layers or clouds. The layers are zigzag, circular or in straight bands (onyx). Occurs in irregular rounded masses; not very translucent; not altered by heat or acids; cannot be cut with a knife nor split into plates; takes a high polish; lustre glassy; gravity 2.5. VALUE.--Used for jewelry and ornamental work, mortars, vases, knife-handles, burnishers, etc. The colors are deepened by boiling in oil and then in sulphuric acid. LOCALITIES.--Found in granite and trap regions, generally by the shores of rivers, lakes and the sea; as, north-west shore of Lake Superior; Missouri, Columbia, Colorado and Connecticut Rivers; Crescent City, Cal.; Hancock County, Ga.; near Tampa Bay, Fla.; Fulton, Penn.; Yellowstone Lake, Wy.[3] 2.-ALUM. Occurs in mealy or solid crusts, often fibrous; dissolves in water; tastes sweetish-astringent; melts and froths up when heated. VALUE.--Extensively used in dyeing and calico-printing, candle-making, dressing skins, clarifying liquors and in pharmacy. LOCALITIES.--Found incrusting and impregnating dark slaty rocks, with yellow streaks. Cape Sable, Md.; Cleveland County, N. C.; coal slates on Ohio River, and in caves in Sevier, De Kalb, Coffee and Franklin Counties, Tenn.; also Esmeralda and Storey Counties, Nev. 3.--AMETHYST. Same as _Rock Crystal_, but colored purple or bluish violet. Generally in clustered crystals. VALUE.--When clear and finely colored, it is a favorite gem. LOCALITIES.--Usually found with agate. Keweenaw Point, Pic Bay and Gargontwa on Lake Superior; Bristol, R. I.; Surry, N. H.; East Bradford, Aston, Chester, Thornbury, Edgemont, Sadsbury, Birmingham, Middletown and Providence, Penn.; Greensboro, N. C. 4.--ANTHRACITE. Occurs massive; compact; high lustre; brittle; breaks with a curved surface; will not scratch marble; burns, but not readily, with a pale blue flame and little smoke; will not form coke by roasting; gravity 1.4 to 1.8. VALUE.--Used for fuel and sometimes cut into inkstands, etc. LOCALITIES.--Found in beds between slates and sandstones, and east of the Alleghany range only, as Eastern Pennsylvania; Portsmouth, R. I.; Mansfield, Mass.; North Carolina. No workable beds will be found in New York. The rocks in anthracite regions are tilted, bent and broken, never level to any great extent. Impressions of leaves are good indications. 5.--ANTIMONY ORE. Occurs fibrous or granular; color lead gray, often tarnished; shining lustre, brittle; but thin pieces can be cut off with a knife; melts in a candle, at a high heat passing off in vapor; gravity 4.5. VALUE.--The source of the antimony of commerce, containing seventy per cent.