Augite is usually black, with stubby crystals. It is a common primary mineral in basalt, gabbro and peridotite and a metamorphic mineral in gneiss and schist.
Augite is the most common pyroxene, with the formula (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6. It is the typical pyroxene in mafic igneous rocks. (more below)
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