metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: typically white to gray, can be tan or pink; Luster: Vitreous to dull; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- typically white to gray, can be tan or pink
- Luster
- Vitreous to dull
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: 7 on Mohs scale; Color: typically white to gray, can be tan or pink; Luster: Vitreous to dull; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
Formation & geological history
Formed from the metamorphism of quartz-rich sandstone under intense heat and pressure, typically during mountain-building events (orogenic belts). It can range from Precambrian to Cenozoic in age.
Uses & applications
Used primarily in construction for road ballast, flooring, and wall facing. High-purity quartzite is used to produce silica sand for glass making and metallurgy.
Geological facts
Quartzite is so hard and chemically resistant that it often forms the caps of ridges and mountains because it resists weathering better than surrounding rocks.
Field identification & locations
Identify by its extreme hardness (cannot be scratched by steel) and its crystalline appearance where individual sand grains have fused together. Commonly found in folded mountain ranges globally.
More like this
