48.—Mica.
Occurs in masses, which can be split into very thin, elastic leaves; pearly lustre; at a high heat becomes opaque; gravity 3.
Value.—Used for doors of stoves, etc.
Localities.—Found in granite regions. Buckfield, Freeport and Oxford, Me.; Acworth, Grafton and Alstead, N. H.; Chesterfield, Barre, Mendon, South Royalston, Brimfield, Goshen and Russell, Mass.; Monroe, Haddam and Middletown, Conn.; Warwick, Edenville, Edwards, Monroe and Greenfield, N. Y.; Pennsbury, Thornbury, Unionville, Middletown and Chestnut Hill, Pa.; Jones’ Falls, Md.