metamorphic
Quartzite
Metamorphic Quartzite (SiO2)
Hardness of 7 on the Mohs scale, colors range from white and gray to shades of pink, brown, and yellowish-orange due to iron oxide staining. Exhibits a vitreous to greasy luster, massive crystal structure with interlocking quartz grains, and uneven to conchoidal fracture.
Identified More metamorphic →
Explore Quartzite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale, colors range from white and gray to shades of pink, brown, and yellowish-orange due to iron oxide staining. Exhibits a vitreous to greasy luster, massive crystal structure with interlocking quartz grains, and uneven to conchoidal fracture.
Formation & geological history
Formed from quartz-rich sandstone or chert that has been subjected to immense heat and pressure through regional or contact metamorphism, typically taking millions of years in tectonic convergent zones.
Uses & applications
Used in construction as crushed stone for road bases, railway ballast, building facades, and decorative landscaping. High-purity quartzite is used to produce silicon metal and ferrosilicon.
Geological facts
Quartzite is extremely durable and resistant to weathering, which explains why quartz-rich mountain ridges often stand out as high peaks or ridges after surrounding softer rocks have eroded away.
Field identification & locations
Can be identified in the field by its extreme hardness (will easily scratch glass and cannot be scratched by a knife) and the sugary texture of interlocking quartz crystals visible on broken surfaces. Found worldwide in ancient mountain belts.
More like this
