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)
monocliniccommonsulfates
Selenite
CaSO₄·2H₂O
A clear, colorless to pale yellowish bladed crystal of gypsum, measuring 11 cm across. It exhibits excellent transparency and a vitreous luster, characteristic of the selenite variety.
Selenite Physical Properties
Mohs Hardness
1.5Crystal System
monoclinicLuster
vitreousStreak Color
whiteCleavage
perfect on {010}, distinct on {100} and {111}Fracture
conchoidalSpecific Gravity
2.32Colors
clear, colorless, white, pale yellow, pale brownTransparency
transparentType Locality
Not specified in metadata, but found worldwide (e.g., Naica, Mexico; Cave of the Crystals)Mineral Group
sulfatesUses
collector, ornamental, sculpture, source of plaster of ParisAssociated Minerals
halite, anhydrite, sulfur, calcite, dolomite, clays, iron oxidesRarity
commonGeological Context
Selenite forms as layers or crack fillings in sedimentary rocks, frequently associated with red beds. It also precipitates as bladed crystals in soils from groundwater.
