GEOGRAPHICAL DISTRIBUTION
India, Canada, and the United States produce about 98 per cent. of the sheet mica of the world. The output of India and of the United States is entirely muscovite, whereas the Canadian production is almost entirely phlogopite. Brazil and Argentina have become important producers in the last two years, and German East Africa was becoming of considerable importance immediately before the war. South Africa, Guatemala, Ceylon, Madagascar and Australia have produced small amounts of mica and may be considered as potential sources of supply.
India produces about 65 per cent. of the sheet mica of the world, and is the most important source of high quality muscovite. The two principal producing regions are the Hazaribagh district, in the Province of Behar, and Orissa, in Bengal, and the Nellore district, Madras Presidency.
The output of Canada is practically all phlogopite or amber mica, of which that country is the world’s principal source. The important producing districts are north of the city of Ottawa, in the Province of Quebec, and in the central part of the Province of Ontario. The Lacey mine, in Ontario, has been the largest producer of amber mica in Canada for many years.
The United States produces about 15 per cent. of the sheet mica muscovite of the world. In terms of value, about 70 per cent. of the American product comes from North Carolina, and 23 from New Hampshire. Other districts are insignificant: 3 per cent. comes from Virginia, 1 from South Dakota, and 3 from Georgia, Alabama, Idaho, and Colorado taken together.
The principal sources of mica in Brazil are the states of Bahia, Sao Paulo, Goyaz and Minas Geraes. The two last mentioned are particularly important. The deposits are widely scattered over a large area.
Production of mica in Argentina has been incidental until very recently and the development has been slight. Deposits are numerous but are of special importance in the provinces of Cordoba, San Luis and San Juan. As far as is known muscovite is the only mica produced.
Considerable activity has been shown in mica mining in Guatemala and shipments have been made quite regularly to this country. The mica, however, is of inferior grade and has not found favor in American markets.
The production of the former German East Africa is confined entirely to muscovite mica found in the districts of the Ulguru Mountains and neighboring ranges. Considerable quantities of high-grade material were exported to Germany before the war. The mica mines in German East Africa were worked during the war under the direction of the British Ministry of Munitions. The district is of importance as a future source of high-grade muscovite.
The principal locality in South Africa is near Leydersdorp, in the Northern Transvaal. Both muscovite and amber mica are reported from this area.