augite

A mineral called by Hauy, pyroxene; often found in distinct crystals. Its secondary forms are all six or eight-sided prisms. Sometimes it appears in hemitrope crystals. It has a foliated structure, and is harder than hornblend. The varieties are common augite, sahlite, fassaite, and cocolite. The omphacite of Werner appears also to be a variety; and the common augite, found near the lake Baikal, has been called Baikalite. Werner divides augite into four sub-species; granular, foliated, conchoidal, and common; and there is a variety called slaggy augite.