Azulicite (Sanidine variety)
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameAzulicite (Sanidine variety)
Chemical FormulaKAlSi3O8
Mohs Hardness6
Crystal Systemmonoclinic
Lustervitreous
Streak Colorwhite
Cleavageperfect in two directions ({001} and {010})
Fractureconchoidal to uneven
Specific Gravity2.56
Colorscolorless, light blue, violet, yellowish
Transparencytransparent
Type LocalityMina La Pili, Carmago, Chihuahua, Mexico
Mineral GroupSilicates (Tectosilicates, Feldspar group)
Usesjewelry, collector's item
Associated Mineralsquartz, biotite, hornblende, plagioclase
Rarityuncommon
Description
A rectangular, faceted gemstone displaying a prominent blue schiller or adularescence, with clear to slightly yellowish facets at the ends.
Geological Context
Sanidine typically forms in high-temperature, rapidly cooled igneous rocks, such as volcanic lavas (rhyolites, trachytes) and hypabyssal intrusions, often as phenocrysts.
