GRAPHITE, crystalline or amorphous car bon. It crystallizes in rombohedral forms, but is commonly foliated or earthy. It has a gray metallic lustre, and is greasy to the fed. Its hardness is 1-2 and its specific gravity 2.1-2.2. The better grades of natural graphite contain 90-95 per cent of carbon, the impurities being chiefly earth or rock. It occurs as an original mineral, minutely disseminated through many igneous rocks. Its most common occurrence,. however, is in beds of highly metamorphosed rocks of sedimentary origin, probably repre senting original organic matter, from which, by heat and pressure, the volatile hydrocarbons have been driven off, leaving pure carbon be-: hind. It probably represents the extreme end i product in the same process that forms coal (q.v.), Most of the domestic supply comes from pre-Cambrian rocks in the Adirondack region of New York. Rhode Island is also a producer. Canada and Bavaria yield, important quantities, while Ceylon is the world's chief producer. Because of its refractory character it is used in the manufacture of high tempera ture crucibles. It is also used in paint, and as a lubricant. Much of it is used in making lead pencils (so-called ublacklead)). Graphite is made artificially at Niagara Falls, N. Y., where large quantities of anthracite coal and other forms of amorphous carbon are converted to this product. The electric furnace process ren ders it to make graphite of the high est purity, and also possessing certain definite chemical and properties.
The annual electric furnace production of graphite at Niagara Falls amounts to over 13, 000,000 pounds, the production increasing rapidly to meet the demand. About 30 different grades of artificial graphite are now produced. The art of making graphite in the electric fur nace was invented and developed by Edward G. Acheson (q.v.) to whom credit for creating carborundum (q.v.) is also due. Dr. Acheson
is also the inventor of deflocculated graphite, which is graphite reduced to the molecular condition, this latter process being operated in Port Huron, Mich. In the deflocculated form graphite diffuses itself through water and oil, and is the •basis for valuable new lubricants known as oildag and aquadag (qq.v.). See ELECTROCHEMICAL INDUSTRIES.
The amount of crystalline or flake graphite mined in the United States in 1916 exceeded that of any previous year, and showed an increase of 55 per cent in quantity and 117 per cent in value over the output for 1915. The 18 mines which were active pro duced 10,931,989 pounds, valued at $914,748. Alabama continued to be the leading producer, her seven mines yielding 5,226,940 pounds-48 per cent of the production of the whole coun try. Pennsylvania's five mines. with a corn bind output of 1,095,716 pounds, retained her in second place. In New York, three mines were active; in California, one; in Montana, one, and in Texas, one. Of amorphous graphite, the domestic production totaled 2,622 tons, mined in five States — Colorado, Michigan, Nevada, North Carolina and Rhode Island.
Imported graphite continued to dominate the market, constituting 85.4 per cent of the total supply of the crystalline form — mostly from Ceylon — and 80.5 per cent of the amorphous supply—largely from Mexico and Chosen. The amount imported in 1916 was 64,120,000 pounds of crystalline graphite and 10,857 tons of amorphous graphite. The enormous in crease in the 1916 consumption of graphite in the United States above that of 1915, amount ing to 66 per cent in crystalline, and 156 per cent in amorphous graphite, is attributed to the remarkable expansion in the electrochemical industries, and the consequent demand for graphite electrodes.