Gypsum Rose
Image: “Jon Zander (<a href="//commons.wikimedia.org/wiki/User:Digon3" title="User:Digon3">Digon3</a>)" (CC BY-SA 3.0)
Mineral NameGypsum Rose
Chemical FormulaCaSO₄·2H₂O
Mohs Hardness2
Crystal Systemmonoclinic
Lusterearthy
Streak Colorwhite
Cleavageperfect on {010}, distinct on {100} and {111}
Fractureconchoidal to uneven
Specific Gravity2.32
Colorswhite, tan, brown
Transparencytranslucent
Type LocalitySahara Desert, Oklahoma (USA), Arizona (USA)
Mineral GroupSulfates
Usescollector, decorative
Associated Mineralsquartz (sand), clay minerals
Raritycommon
Description
This specimen is a 'desert rose' formation of gypsum, characterized by its rosette-like aggregation of tabular crystals. It exhibits a sandy, light brown to off-white color due to incorporated sand grains.
Geological Context
Gypsum roses form in arid, shallow evaporitic environments such as playas or sabkhas, where gypsum crystallizes from saline groundwater, incorporating sand grains as it grows into distinctive flower-like aggregates.
