PYROXENE
pyroxene
(noun) any of a group of crystalline silicate mineral common in igneous and metamorphic rocks
Source: WordNet® 3.1
Etymology
Noun
pyroxene (plural pyroxenes)
(mineral) Any of a group of crystalline minerals containing silicates of iron, magnesium and calcium.
Source: Wiktionary
Pyr"ox*ene, n. Etym: [F. pyroxène, from Gr. (Min.)
Definition: A common mineral occurring in monoclinic crystals, with a
prismatic angle of nearly 90º, and also in massive forms which are
often laminated. It varies in color from white to dark green and
black, and includes many varieties differing in color and
composition, as diopside, malacolite, salite, coccolite, augite, etc.
They are all silicates of lime and magnesia with sometimes alumina
and iron. Pyroxene is an essential constituent of many rocks,
especially basic igneous rocks, as basalt, gabbro, etc.
Note: The pyroxene group contains pyroxene proper, also the related
orthorhombic species, enstatite, bronzite, hypersthene, and various
monoclinic and triclinic species, as rhodonite, etc.
Source: Webster’s Unabridged Dictionary 1913 Edition