metamorphic
Quartzite
Quartzite (primarily SiO2)
Hardness: 7 on Mohs scale; Color: Pinkish-tan to light purple; 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
- Pinkish-tan to light purple
- 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: Pinkish-tan to light purple; 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 metamorphism of quartz sandstone under high heat and pressure, causing recrystallization of sand grains. Commonly formed during mountain-building events (orogenies).
Uses & applications
Used in construction as road ballast, flooring, and wall facing. Decorative use in landscaping and architecture. Some high-purity varieties are used to produce glass and abrasives.
Geological facts
Quartzite is so hard and durable that it often forms the resistant caps of many ridges and hills. It is harder than the steel of a knife blade and can easily scratch glass.
Field identification & locations
Identify by its extreme hardness and grainy texture that looks like sand but cannot be rubbed off. Found in mountain ranges and eroded stream beds. It won't fizz with acid like limestone.
More like this
