APATITE (from Gk. circirn, apate, deceit, as the mineral has often been mistaken for other minerals). A mineral consisting of phosphate with some chloride and fluoride of calcium, its composition being represented by the formula, Ca ((IF ),. It occurs both in crys talline and amorphous form, and is largely used in the manufacture of fertilizers, for which it is valuable on account of the contained phos phoric acid. It occurs in both stratified and crystalline '(metamorphic and igneous) rocks, especially in the latter. It is thus found in the older crystalline rocks in Canada, New York, Maine, and New Jersey; in Europe, it is known in England, France. Saxony, Tyrol, Bohemia, Spain, Norway. etc.: hut the only deposits of economic importance are those of Canada, Norway, and Spain. Most of the Canadian material that has been shipped contains eighty-five per cent. of the phosphate of lime. In recent years the enormous deposits of rock phosphate or amorphous phos phate of lime have seriously injured the Canadian trade. Amorphous phosphate is a name given to non-crystalline deposits of phos phate of lime occurring in more or less abundance at certain localities and of importance as a source of fertilizer. In the United States the most important deposits are in South Caro lina, Florida, and Tennessee, but a small supply has also been obtained front Pennsylvania. The Florida deposits, which have been worked since 18SS, are found near the western coast. They occur as lumps imbedded in clay, known as Rock Phosphate; in pebble agglomerations, known as Laud Pebble: or as a mixture of small pebbles and sand in the river bottoms called River Peb ble. The latter mixture is obtained by dredg ing, the sand being eventually separated by screening. The South Carolina deposits are found in an area about sixty miles long, between Charleston and Beaufort. The phosphate occurs in nodules buried in sand and clay, the produc tive bed being one to two feet thick. An acre yields four hundred to twelve hundred tons. The South Carolina district was opened up in 1867. Both the Florida and South Carolina deposits occur associated with rocks of Eocene and Miocene ages, and many teeth of sharks, elephants, etc., together with bones, are found with the phosphate. The phosphoric acid of the mineral is supposed to owe its origin to the accumulation of excrement and decaying animal matter deposited along the shores or in pools during Tertiary times, and to subsequent local replacement of limestone, or to concre tionary segregation of phosphate of lime. In south central Tennessee, the phosphate is as sociated with Devonian rocks. The phosphate industry of the United States has assumed great importance in recent years, and much of the material is shipped to foreign countries.
The recent development of large deposits known to exist in Algiers may cause serious competi tion with the American industry. Crude rock containing less than fifty per cent, of calcie phos phate is unsalable. Siliceous impurities are in ert, but alumina and ferric oxide are bad, because they tend to change the refined phosphate back to an insoluble condition. Lime, if present, neu tralizes some of the sulphuric acid used in the manufacture of the fertilizer. The price of phos phate varies from year to year, and with its grade. That from Tennessee may bring as little as $1.60 per ton, while the hard rock from Florida may bring as touch as $5.00 per ton. The importance of Canada as a producer of phosphate has been greatly lowered by the development of the American beds. Those of Florida have as sumed great predominance, for the ease with which the material can be mined, and by reason of their proximity to shipping points; the latter feature having been an important factor in the development of a large export trade.
For more particular information the reader is referred to the general paper by Adolphe Carnot: "Sur les variations observes dens la composition des :wadies, * * • Remarques sur he gisement et le mode de formation de ees phos phates" in the Aniiales des Mines, Volume X. (Paris, 1S96). Papers descriptive of the phos phate deposits of particular regions are: Bran ner, "The Phosphates of Arkansas," in the Transactions of the American Institute of Mining Engineers, Volume XXVI. (New York, 1896) ; Hayes, "The Tennessee Phosphates," in the Six teenth Annual Report of the United States Geological Surrey, Part IV. ( Washington, 1895).
BIBLIOGRAPHY. Brown, "The Phosphate Rock Bibliography. Brown, "The Phosphate Rock Deposits of Tennessee during 1897," United States Geological Surrey, Nineteenth Annual Re port, Part VI. (continued) (Washington, 1898) ; MeCallie, "A Preliminary Report on a Part of the Phosphates and Marls of Georgia," Georgia Geological Surrey Bulletin, No. 5-A (Atlanta, 1896) ; Eldridge, "A Preliminary Sketch of the Phosphates of Florida." Transactions of the American Institute of Mining Engineers. Volume XXI. (New York, 1891) ; Smith, "The phates and Marls of Alabama," Transactions of the American Institute of Mining Engineers, Vol ume XXV. (New York, 1895) ; Penrose, "The Nature and Origin of Deposits of Phosphate of Lime," Bulletin No. 46, rnited States Geological Surrey; Small, "The Phosphate Mines of Can ada," Transactions of the American Institute of Mining Engineers, Volume XXI. (New York, 1891) : and Wyatt, F., The Phosphates of Amer ica (New York, 1891).