metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: Grayish-white with dark inclusions; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal (granular texture); Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- Grayish-white with dark inclusions
- 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 dark inclusions; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal (granular texture); 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. Geological age varies by location, often Precambrian or Paleozoic.
Uses & applications
Used in construction as crushed stone for roadbeds, as a decorative stone in landscaping, in glass manufacturing if pure enough, and frequently used for tool-making by prehistoric humans.
Geological facts
Quartzite is so hard and chemically resistant that it often forms the resistant caps of ridges and mountains. It is harder than a steel knife and will easily scratch glass.
Field identification & locations
Identify by its extreme hardness and the way it breaks through the quartz grains rather than around them (unlike sandstone). Commonly found in folded mountain belts globally.
More like this
