metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: typically white, gray, or pink; Luster: vitreous to dull; Crystal structure: hexagonal (trigonal); Grainy, sand-paper like texture that breaks across grains.
- Hardness
- 7 on Mohs scale
- Color
- typically white, gray, or pink
- 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: typically white, gray, or pink; Luster: vitreous to dull; Crystal structure: hexagonal (trigonal); Grainy, sand-paper like texture that breaks across grains.
Formation & geological history
Formed by the metamorphism of quartz-rich sandstone under intense heat and pressure, typically during mountain-building events in the Precambrian or Paleozoic eras.
Uses & applications
Used extensively in road construction, as railroad ballast, in the manufacture of glass and ceramics, and as a decorative stone in architecture and landscaping.
Geological facts
Quartzite is so hard and chemically resistant that it often forms the caps of ridges and mountains because it weathers much more slowly than surrounding rocks.
Field identification & locations
Identify by its extreme hardness (cannot be scratched by steel) and lack of reaction to acid. Common in metamorphic belts worldwide. Collectors look for high-purity or colorful crystalline varieties.
More like this
