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)
triclinicuncommonsilicates (tectosilicates, feldspar group)
Anorthite
CaAl2Si2O8
This image displays a blocky, white to grayish specimen of Anorthite, showing some of its characteristic cleavage planes and a somewhat dull to vitreous luster.
Anorthite Physical Properties
Mohs Hardness
6Crystal System
triclinicLuster
vitreousStreak Color
whiteCleavage
perfect on {001} and {010}, good on {110}Fracture
uneven to conchoidalSpecific Gravity
2.76Colors
white, gray, colorless, yellowish, reddishTransparency
transparent to translucentType Locality
Hokkaido, Japan (among others)Mineral Group
silicates (tectosilicates, feldspar group)Uses
collector's item, scientific researchAssociated Minerals
pyroxenes, olivine, magnetite, other plagioclase feldsparsRarity
uncommonGeological Context
Anorthite is a primary mineral in mafic and ultramafic igneous rocks like gabbro, basalt, and anorthosite, forming at high temperatures. It can also be found in some high-grade metamorphic rocks.
