Gabbro

A gabbroid composed of 10-90% Ca-dominant plagioclase and >5% clinopyroxene. A group of basic intrusive igneous rocks composed principally of basic plagioclase (commonly labradorite or bytownite) and clinopyroxene (augite), with or without olivine and orthopyroxene; also, any member of that group. It is the approximate coarse-grained/intrusive equivalent of basalt. Apatite, magnetite, and ilmenite are common accessory minerals. Commonly dark-colored.