Pyroxinites

Pyroxenites are a group of ultramafic igneous rocks. They are primarily composed of one or more pyroxene minerals. The most common pyroxene found in pyroxenites is clinopyroxene, but orthopyroxene can also be a significant component. Other minerals are typically present in subordinate amounts, such as olivine, plagioclase feldspar, spinel, or amphibole.

These rocks are generally dark-colored and have a coarse-grained texture. Pyroxenites are found in various geological settings, including layered intrusions within the Earth's crust and as xenoliths within other volcanic rocks. They are also a common component of the Earth's upper mantle. Their formation is associated with magmatic processes deep within the Earth.

The classification of pyroxenites is based on the specific types and proportions of pyroxene minerals present. For example, clinopyroxenites are dominated by clinopyroxene, while orthopyroxenites are dominated by orthopyroxene. Websterites contain significant amounts of both clinopyroxene and orthopyroxene. Due to their ultramafic nature, pyroxenites are typically low in silica and rich in magnesium and iron. They are not generally considered ore-bearing rocks, though some may be associated with economic mineral deposits.