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,Ti)(Si,Al)2O6
The image displays several small, dark, prismatic to blocky crystals, likely black or very dark green, exhibiting some visible cleavage planes.
Augite Physical Properties
Mohs Hardness
5.5Crystal System
monoclinicLuster
vitreousStreak Color
white to grayish-greenCleavage
Good in two directions at nearly 90 degrees (87 and 93 degrees)Fracture
unevenSpecific Gravity
3.4Colors
black, dark green, brownish-blackTransparency
opaqueType Locality
Widespread; often found in Oregon, USAMineral Group
Silicates (Pyroxene Group)Uses
geological study, rock-forming mineralAssociated Minerals
olivine, plagioclase feldspar, hornblende, magnetite, ilmeniteRarity
commonGeological Context
Augite is a common rock-forming mineral found in mafic and ultramafic igneous rocks such as basalt, gabbro, and peridotite, crystallizing from magma. It can also occur in some high-grade metamorphic rocks.
