Augite

Augite is a silicate with composition (Ca, Mg,Fe)₂(Si,Al)₂O₆. This sample is about 8x12 cm and is from Vesuvia, Campania, Italy. It is formed with phlogopite. The sample is on display at the Smithsonian Museum of Natural History.

Augite is a basic silicate mineral with high content of iron and magnesium, a so-called "ferromagnesian" mineral of the pyroxene grouping. This identifies it as a high-crystallization-temperature dark silicate, formed at early stages of the Bowen reaction series.

Augite is often found as crystals in basalt.