- any of a very common group of minerals of many varieties, silicates of magnesium, iron, calcium, and other elements, occurring as important constituents of many kinds of rocks, especially basic igneous rocks.
- any of a group of silicate minerals having the general formula ABSi 2 O 6, where A is usually calcium, sodium, magnesium, or iron, and B is usually magnesium, iron, chromium, manganese, or aluminium. Pyroxenes occur in basic igneous rocks and some metamorphic rocks, and have colours ranging from white to dark green or black. They may be monoclinic (clinopyroxenes) or orthorhombic (orthopyroxenes) in crystal structure. Examples are augite (the most important pyroxene), diopside, enstatite, hypersthene, and jadeite
