Image: <bdi><a href="https://www.wikidata.org/wiki/Q126871365" class="extiw" title="d:Q126871365"><span title="photographer from the United States">Shannon Heinle</span></a></bdi> (CC0)
monocliniccommonSilicates (Pyroxene Group)
Augite
(Ca,Na)(Mg,Fe,Al)(Al,Si)2O6
This sample shows a dark, blocky, prismatic crystal of augite, approximately 4.5 cm across, with a somewhat dull to vitreous luster typical of the mineral.
Augite Physical Properties
Mohs Hardness
6Crystal System
monoclinicLuster
vitreousStreak Color
white to grayish-greenCleavage
Two distinct cleavages at nearly 90 degrees (87 and 93 degrees)Fracture
uneven to conchoidalSpecific Gravity
3.4Colors
dark green, black, brownish-blackTransparency
opaque to translucentType Locality
Eganville, Ontario, CanadaMineral Group
Silicates (Pyroxene Group)Uses
rock-forming mineral, collector specimensAssociated Minerals
plagioclase, olivine, magnetite, hornblendeRarity
commonGeological Context
Augite is a common and important rock-forming mineral found in many mafic and ultramafic igneous rocks such as gabbro and basalt, as well as in some high-grade metamorphic rocks like amphibolites and granulites.
