Mafic

Mafic is an adjective describing a silicate mineral or rock that is rich in magnesium and iron, and hence is a portmanteau of "magnesium" and "ferric". Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include basalt, dolerite and gabbro.