metamorphic
Quartzite
Quartzite (primarily SiO2)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: typically white, gray, or tan; Luster: vitreous to dull; Crystal structure: Trigonal (as quartz); Breakage: conchoidal or irregular; Texture: Granular and crystalline.
- Hardness
- 7 on Mohs scale
- Color
- typically white, gray, or tan
- 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 tan; Luster: vitreous to dull; Crystal structure: Trigonal (as quartz); Breakage: conchoidal or irregular; Texture: Granular and crystalline.
Formation & geological history
Formed through the regional or contact metamorphism of quartz-rich sandstone. Under intense heat and pressure, the individual quartz grains recrystallize and fuse together, creating a dense, interlocking structure.
Uses & applications
Used as crushed stone for road construction and railway ballast; also used as a dimension stone for flooring, countertops, and decorative wall cladding due to its durability.
Geological facts
Quartzite is so hard that it will scratch glass and steel. In the Stone Age, it was occasionally used as a source for stone tools, though it is much harder to work with than flint or obsidian.
Field identification & locations
Identify by its extreme hardness (cannot be scratched by a steel nail) and its sugary, crystalline appearance. Unlike marble, it will not fizz when exposed to dilute hydrochloric acid. It is found globally in mountainous regions where ancient sedimentary basins have been uplifted.
More like this
