ASPHALT.- Besides the 688,334 tons of asphalt produced from petroleum, natural asphalts and bituminous rocks are mined at various places in Utah. California, Kentucky and Texas. While much of the material is used for roads, the minerals gilsonite, grahamite, wurtzilite and ozocerite have many uses in the arts.
Elsams.— Used principally as white pigment notably in " lithopone, " is mostly mined in Georgia. Missouri, Ten nessee, Kentucky, South Carolina, North Carolina, Ala bama and southwestern Virginia. Production has been increasing steadily and in 1910 it passed the $1,000,000 mark.
Bisartrrn.— This metal is used mostly in alloys for safety fuses, and in medicine. It is separated from various ores at several smelters and is also mined in small amounts in Colorado and Utah.
Bostax.— This salt is produced from colemanite mined in a few localities in southern and southeastern California.
The famous Death Valley mines are no longer large producers.
Separated from salt brines at several places Michigan and West Virginia and at Pomeroy, Ohio. It is used extensively in photography, for dissolving gold and in various chemicals and medicines.
Produced in small amount as a by-product in lead and zinc smelting, is used as an alloy for safety plugs of automatic fire extinguishers, for increasing the malle ability of silver for silverware, in pigments and in dental amalgam. Its value is about $1.50 a pound.
Crusrir.— There is almost an unlimited supply of limestone and other materials available for making Portland and other cements but their utilization depends on the demand and proximity to market. Pen_ nsylvama leads in its manu facture but Indiana, Iowa, California and New York are important producers.
Chromite or chromate of iron is the principal source of this metal which is in great demand for harden ing steel. It is also used for pigments, notably in one which gives khaki its distinctive tint. Shasta County, Cal., is the largest producer but additional supplies come from other parts of that State and from Oregon, Wyoming and Maryland.