AZURITE (from its azure color). A blue basic cupric carbonate, containing about 55 per cent. of copper, and crystallizing in the mono clinic system. It differs in composition from malachite only by containing more carbonic acid Mid less water. With the blow-pipe, azurite gives a metallic bead, while it is soluble in acids and ammonia, and in such solutions can readily be tested for copper. It is usually found with mala chite and other ores of copper, and the specimens from Chessy, near Lyons, France, are noted for their fine crystallization, and are called elicssy lite. The azurite from Siberia is frequently cut in Russia into thin slabs. and used as veneering for table-tops, and the like. Crystals of azurite, found in Arizona, are highly regarded as gems, although they are too small to be extensively used. The amorphous variety of azurite is a valuable ore of copper: it occurs in great quan tities in some of the Arizona mines, where it is actively wrought. In the Clifton district it is
found in limestone and is accompanied by other ores of copper, including malachite, •uprite, melaconite, and native copper, and by limonite.
The Copper Queen Aline in the Bisbee district has produced solid masses of azurite and mala chite weighing several tons. The mineral in all cases is probably to be regarded as of secondary origin: i.e. it has been derived from other cop per minerals by the natural processes of oxida tion and hydration. The original sources of ma terial are copper sulphides, which are still found in the deeper portions of the mines where the weathering agencies have not penetrated. Azur ite has also been used as a pigment.