HYPERSTHENE

Noun

hypersthene (countable and uncountable, plural hypersthenes)

(mineral) An inosilicate that is an orthorhombic pyroxene.

Source: Wiktionary

Hy"per*sthene, n. Etym: [Gr. hyperstène.] (Min.)

Definition: An orthorhombic mineral of the pyroxene group, of a grayish or greenish black color, often with a peculiar bronzelike luster (schiller) on the cleavage surface.

Source: Webster’s Unabridged Dictionary 1913 Edition