What does augite mean?
Augite is a rock-forming mineral belonging to the pyroxene group, typically appearing as dark green, brown, or black crystals with a short prismatic habit. Chemically a calcium–magnesium–iron silicate, it is one of the most common minerals in mafic and ultramafic igneous rocks such as basalt, gabbro, and peridotite, and it also occurs in some metamorphic rocks. The name derives from the Greek 'augē', meaning lustre or brightness, an ironic label given the mineral's often dull appearance. For geologists, augite is a valuable indicator mineral: its composition and texture help reveal the conditions under which a rock crystallised. The adjective 'augitic' describes rocks or textures rich in the mineral. Although rarely encountered outside scientific contexts, augite is fundamental to understanding the Earth's volcanic and plutonic processes, making it a staple of petrology courses and field guides worldwide.
nounA dark green to black rock-forming mineral of the pyroxene group, typically occurring in igneous rocks such as basalt and gabbro.
- A dark green to black pyroxene mineral, (Ca,Mg,Fe)₂Si₂O₆, common in mafic igneous rocks such as basalt and gabbro.
"The thin section revealed lustrous crystals of augite embedded in the basalt."
"Under the microscope, the basalt showed abundant phenocrysts of augite and plagioclase."
"The geologist identified the black prismatic crystals as augite by their distinctive cleavage angles."
Rarely used; the singular serves as a mass noun in most geological contexts. The plural appears mainly when counting distinct crystals.
"The slide contained numerous augites of varying grain size."
Augite takes its name from the Greek word for 'lustre' — but despite the flattering name, it's usually a dull, nearly black mineral found in ordinary volcanic rock.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of augite
The word 'augite' entered English in the early 19th century, borrowed from German 'Augit'. It ultimately derives from the Greek 'augē', meaning 'lustre' or 'bright light', referring to the mineral's occasionally shiny surfaces. Its adjectival derivative 'augitic' follows the standard pattern for mineral names.
Related word forms
How augite is actually used
Augite is a technical term used almost exclusively in mineralogy and geology. It is a mass noun in most geological writing, though plural 'augites' appears when referring to individual crystals.
Easily confused with augite
An augur was a Roman official who interpreted omens; augite is a dark pyroxene mineral.
Agate is a banded, semi-precious variety of chalcedony, whereas augite is a dark rock-forming pyroxene mineral.