The Probert Encyclopaedia of Rocks & Minerals

AUGITE

Augite is an important rock forming mineral of the pyroxene group. Chiefly found in dark coloured igneous rocks, especially those whose magmas were rich in iron, calcium and magnesium. Seldom found in rocks that contain much quartz. A common member of the pyroxene group. Told from the amphibole group by cleavage. It has the formulae (Ca,Na) (Mg,Fe,Al,Ti)(Si,Al)2O6 and a relative hardness of 6. When crystallized it assumes the form of short, slightly rhombic prisms, with their lateral edges replaced, and terminated at one or both extremities by numerous planes. A transparent green variety found at Zillerthal, in the Tyrol, is used in jewelry.
Research Augite