Autunite

[So named because found near Autun, in the department of Saône-etLoire, in France.] Min.: An orthorhombic mineral, of a citron or sulphur-yellow colour. The hardne is 2 to 25; the sp. gr., 3.05 to 3-19; the lustre on one face pearly, on others adamantine. It is a translucent and optically biaxial. Composition: Phosphoric acid, 13:40 to 15-20; sesquioxide of uranium, 56-47 to 61.73; water, 15:48 to 20; with smaller amounts of lime, magnesia, protoxide of inanganese, baryta, and oxide of tin. Formerly found at South Ba et, Wheal Edwards, and near St. Day, in England; now at St. Symphorien, near Autun, in France; in Ru ia, America, . (Dana.)