Quartzite
Image: Gennady Grachev from Moscow, Russia (CC BY 2.0)
Mineral NameQuartzite
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak ColorWhite
CleavageNone
Fractureconchoidal/splintery
Specific Gravity2.65
Colorsreddish-brown, white, grey, pink, yellow
Transparencytranslucent/opaque
Type LocalityWorldwide
Mineral GroupMetamorphic rock
Usesbuilding material, dimension stone, road aggregate, decorative stone
Associated Mineralsquartz, hematite, feldspar, mica
Raritycommon
Description
A large, reddish-brown block of rock with a somewhat granular texture and faint, parallel layering, suggesting its sedimentary origin before metamorphism.
Geological Context
Quartzite is a nonfoliated metamorphic rock formed from pure quartz sandstone through intense heat and pressure, typically in orogenic belts. It is extremely durable and resistant to chemical and physical weathering.
