Hypersthene: a mineral belonging to the Pyroxene Group (which also includes Augite, Aegirine, Bronzite, Fassaite, Hedenbergite, Omphacite, and Spodumene) with the chemical formula (Fe,Mg)₂[Si₂O₆]. It is opaque, with a luster ranging from vitreous to metallic and colors varying from green to brown, reddish, and blackish. It crystallizes in the Orthorhombic System and typically forms tabular or columnar crystals with abundant flat surfaces, as well as coarse granular and foliated aggregates. It is found in basic igneous rocks and gneisses.
