Pyroxene Data

The pyroxenes are a family of iron-magnesium silicate minerals that are important in igneous and metamorphic rocks, particularly those with a more mafic (iron-magnesium rich) composition formed at higher pressures and temperatures. Pyroxene minerals include aegirine, augite, diopside, hedenbergite, enstatite, jadeite and spodumene.

Pronunciation: PEER•ox•ine (accent on capitalized syllable)

Color: commonly black to dark green or dark brown

Luster: vitreous

Diaphaneity: translucent, but generally appears to be opaque in hand specimen

Hardness: 5.5-6

Specific gravity: 3.4

Cleavage/fracture: 2 directions at approximately right angles

Other distinguishing properties: The pyroxenes may be mistaken for the amphiboles; however, the two cleavages in amphiboles are at oblique angles of around 60° - 120° and amphiboles (i.e., hornblendes) commonly appear to be rectangular or elongate crystals while pyroxenes (e.g., augite) are more stubby and equi-dimensional.

Specimen Pictures


Klein, C., and Hurlbut, C.S., Jr., 1999, Manual of Mineralogy (after James D. Dana) [21st edition, revised]: New York, John Wiley & Sons, 682 p.

Los Angeles County Museum of Natural History, The Photo Atlas of Minerals:

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