Sanidine
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameSanidine
Chemical FormulaKAlSi3O8
Mohs Hardness6
Crystal Systemmonoclinic
Lustervitreous
Streak Colorwhite
Cleavageperfect in two directions at nearly 90 degrees
Fractureuneven
Specific Gravity2.56
Colorsgrayish-brown, blue, purple
Transparencytranslucent
Type LocalityMina La Pili, Carmago, Chihuahua, Mexico
Mineral GroupSilicates
Usescollector's item, scientific study
Associated Mineralsquartz, biotite, hornblende, plagioclase
Rarityuncommon
Description
This specimen features translucent, prismatic crystals of Sanidine, exhibiting a grayish-brown body color with a striking blue and purple iridescence, characteristic of the Azulicite variety.
Geological Context
Sanidine is a high-temperature potassium feldspar that forms in rapidly cooled felsic volcanic rocks such as rhyolites and trachytes, often as phenocrysts.
