What is "enstatite"

Enstatite \En"sta*tite\, n. [Named fr. Gr. ? 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.

n. (context mineral English) A form of pyroxene consisting solely of magnesium silicate.

Enstatite is a mineral; the magnesium endmember of the pyroxene silicate mineral series enstatite (MgSiO) - ferrosilite (FeSiO). The magnesium rich members of the solid solution series are common rock-forming minerals found in igneous and metamorphic rocks. The intermediate composition, (Mg,Fe)SiO, has historically been known as hypersthene, although this name has been formally abandoned and replaced by orthopyroxene. When determined petrographically or chemically the composition is given as relative proportions of enstatite (En) and ferrosilite (Fs) (e.g., EnFs).