metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: Grayish-white with some iron staining; Luster: Vitreous to dull; Crystal structure: Non-foliated, granular; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7.
- Hardness
- 7 on Mohs scale
- Color
- Grayish-white with some iron staining
- Luster
- Vitreous to dull
Identified More metamorphic →
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 some iron staining; Luster: Vitreous to dull; Crystal structure: Non-foliated, granular; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7.
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone. High heat and pressure cause quartz grains to recrystallize and fuse together, creating an extremely durable rock.
Uses & applications
Used extensively as crushed stone for road construction, railway ballast, and as a decorative stone in landscaping. High-purity quartzite is used to produce glass and silicon metal.
Geological facts
Quartzite is so tough that it often survives intense weathering better than the surrounding rocks, frequently forming the tops of ridges and mountains. It is harder than a steel knife and will easily scratch glass.
Field identification & locations
Identify by its sugary texture and extreme hardness (it will scratch glass and steel). It lacks the bubbly reaction to acid seen in marble. It is commonly found in ancient mountain belts and metamorphic shield areas globally.
More like this
