metamorphic
Quartzite
Quartzite (SiO2 based)
Hardness: 7 on Mohs scale; Color: Grayish-white with slight brownish/iron staining; Luster: Vitreous to dull; Crystal Structure: Granular/interlocking microcrystalline quartz; Cleavage: None (fractures conchoidally or irregularly)
- Hardness
- 7 on Mohs scale
- Color
- Grayish-white with slight brownish/iron staining
- 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: Grayish-white with slight brownish/iron staining; Luster: Vitreous to dull; Crystal Structure: Granular/interlocking microcrystalline quartz; Cleavage: None (fractures conchoidally or irregularly)
Formation & geological history
Formed when quartz-rich sandstone is subjected to high heat and pressure during regional metamorphism, causing quartz grains to recrystallize and fuse together into a dense rock.
Uses & applications
Used extensively in construction as crushed stone for road base, aggregate in concrete, railway ballast, dimension stone, and occasionally decorative landscaping.
Geological facts
Quartzite is extremely resistant to chemical weathering and physical erosion, often forming prominent ridge lines and hilltops in mountainous terrains.
Field identification & locations
Identified in the field by its extreme hardness (scratches glass easily) and granular surface that breaks across quartz grains rather than around them. Common in metamorphic belts worldwide.
More like this
