enstatite

n. [ Named fr. Gr. &unr_; an adversary, because infusible before the blowpipe. ] (Min.) A mineral of the pyroxene group, orthorhombic in crystallization; often fibrous and massive; color grayish white or greenish. It is a silicate of magnesia with some iron. Bronzite is a ferriferous variety. [ 1913 Webster ]