Image: <bdi><a href="https://www.wikidata.org/wiki/Q126871368" class="extiw" title="d:Q126871368"><span title="photographer from the United States">Darla Sondrol</span></a></bdi> (CC0)
monoclinicuncommonSilicates (Feldspar Group)
Anorthoclase
KAlSi3O8
This specimen displays anorthoclase, a grayish-white to colorless mineral, often exhibiting a flattened crystal habit. It can show adularescence, a shimmering phenomenon, especially in its moonstone variety.
Anorthoclase Physical Properties
Mohs Hardness
6Crystal System
monoclinicLuster
vitreousStreak Color
whiteCleavage
Perfect on {001}, good on {010}, at nearly 90 degreesFracture
uneven to conchoidalSpecific Gravity
2.6Colors
white, gray, yellowish, pinkishTransparency
transparent to translucentType Locality
Larvik, NorwayMineral Group
Silicates (Feldspar Group)Uses
ceramic industry, glass manufacturing, gemstone (as moonstone variety), collector's itemAssociated Minerals
quartz, pyroxene, amphibole, biotiteRarity
uncommonGeological Context
Anorthoclase is a high-temperature alkali feldspar, typically found in sodium-rich volcanic rocks such as trachytes, phonolites, and rhyolites, as well as some plutonic rocks.
