Diopside


Diopside is a monoclinic pyroxene mineral with composition MgCaSi<sub>2</sub>O<sub>6</sub>. It forms complete solid solution series with hedenbergite (FeCaSi<sub>2</sub>O<sub>6</sub>) and augite, and partial solid solutions with orthopyroxene and pigeonite. It forms variably colored, but typically dull green crystals in the monoclinic prismatic class. It has two distinct prismatic cleavages at 87 and 93° typical of the pyroxene series. It has a Mohs hardness of six and a specific gravity of 3.25 to 3.55. It is transparent to translucent with indices of refraction of nα=1.663 - 1.699, nβ=1.671 - 1.705 and nγ=1.693 - 1.728. The optic angle is 58° to 63°.