metamorphic
Quartzite
Quartzite (primarily Silicon Dioxide, SiO2)
Hardness: 7 on Mohs scale; Color: typically white to gray, can be yellow or reddish; Luster: vitreous to waxy; Texture: granular, crystalline; Fracture: conchoidal or irregular.
- Hardness
- 7 on Mohs scale
- Color
- typically white to gray, can be yellow or reddish
- Luster
- vitreous to waxy
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 yellow or reddish; Luster: vitreous to waxy; Texture: granular, crystalline; Fracture: conchoidal or irregular.
Formation & geological history
Formed from the metamorphism of quartz-rich sandstone under intense heat and pressure, typically during mountain-building events (orogeny). Age varies by location but can date back hundreds of millions of years.
Uses & applications
Used widely in construction as crushed stone for road ballast, as dimension stone for counter tops and flooring, and occasionally in glassmaking if pure enough.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rocks during erosion, often forming the peaks of ridges and mountains. It is significantly harder than the sandstone from which it originated.
Field identification & locations
Identify by its ability to scratch glass and its grainy, sugary appearance despite being a hard, non-porous rock. Unlike marble, it will not fizz when exposed to acid. Commonly found in metamorphic belts worldwide.
More like this
