Clinopiroxene

Clinopiroxene is a mineral belonging to the clinopyroxene group, which are tectosilicate minerals. Its chemical formula is (Ca,Na)(Mg,Fe2+,Al)Si2O6. Clinopiroxene is a solid solution series with end-members of varying compositions. It is a common constituent of mafic and ultramafic igneous rocks. It can be found in a variety of geological settings, including volcanic rocks, plutonic rocks, and metamorphic rocks. Clinopiroxene is often associated with other pyroxenes such as augite and pigeonite, as well as olivine and plagioclase feldspar. Its color typically ranges from brown to black, though it can also be green or colorless depending on its chemical composition. Clinopiroxene crystallizes in the monoclinic crystal system, forming prismatic or stubby crystals. It is relatively hard, with a Mohs hardness of 5 to 6, and has a vitreous to dull luster. Optical properties are used for its identification in thin section, where it exhibits characteristic interference colors and extinction angles. Variations in the proportions of calcium, magnesium, iron, and aluminum influence its physical and optical characteristics. Clinopiroxene plays a role in understanding the petrogenesis and evolution of igneous and metamorphic rocks.