Augite is a pyroxene, a complex aluminous silicate of calcium, iron, and magnesium, crystallizing in the monoclinic system, and occurring in many igneous rocks, particularly those of basaltic composition. Augite is a part of a solid solution series, which also includes the minerals hedenbergite and diopside.

Augite crystallizes in the monoclinic system. The unit cell is a straight prism of a parallelogram base.