ATACAMITE  , a

mineral found originally in the desert of Atacama, and named by D. de Gallizen in 18oi . It is a cupric oxychloride, having the formula CuC12.3Cu(OH)2, and crystallizing in the orthorhombic system . Its hardness is about 3 and its specific gravity 3.7, while its colour presents various shades of green, usually dark . Atacamite is a comparatively rare mineral, formed in some cases by the action of sea-water on various copper-ores, and occurring also as a volcanic product on Vesuvian lavas . Some of the finest crystals have been yielded by the ATALANTA copper-mines of South Australia, especially at Wallaroo . It occurs also, with malachite, at Bembe, near Ambriz, in West Africa . From one of its localities in Chile, Los Remolinos, it was termed Remolinite by Brooke and Miller . Atacamite, in a pulverulent state, was formerly used as a pounce under the name of " Peruvian green sand," and was known in Chile as arsenillo . (F . W .