Augite
Augite is a calcium-rich clinopyroxene common in basalts on Earth, the Moon and Mars.
Augite is a dark green to black calcium-rich clinopyroxene. It is one of the commonest minerals in basalt and gabbro on Earth and appears in many igneous meteorites.
The best-known augite meteorites are the nakhlites from Mars, named after Nakhla, which fell in Egypt in 1911. They are made mostly of elongated augite crystals, with some olivine, that settled together in a thick lava flow or shallow body of magma about 1.3 billion years ago. Augite also occurs in shergottites, angrites, eucrites and lunar basalts.
In slowly cooled rocks, augite often contains thin exsolution lamellae of low-calcium pyroxene, and in quickly cooled ones it may be zoned, with its composition changing from core to rim as the melt evolved. Measuring those changes lets scientists reconstruct the cooling history of a lava on another world.
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