pyroxene en

A major class of silicate minerals and its members which include about twenty mineral species, among them diopside, rhodonite, jadeite. Pyroxenes are found in many igneous and metamorphic rocks. They are distinguished from the second major class of silicate minerals, amphiboles, by their cleavage planes, characterized by prismatic cleavage at nearly 90 degrees, and a structure of single chains of SiO4 tetrahedra as distinct from amphiboles' double chains.