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Most common pyroxene mineral, occurring chiefly as blocky crystals in basalts, gabbros, andesites, and various other dark igneous rocks. It also is a common constituent of lunar basalts and meteorites and may be found in certain metamorphic rocks, such as pyroxenites. Because the diopside-hedenbergite series and augite are nearly indistinguishable, the term augite is sometimes used to designate any dark green to black pyroxene with monoclinic symmetry (three unequal crystallographic axes with one oblique intersection).
This entry comes from Encyclopædia Britannica Concise. For the full entry on augite, visit Britannica.com.