metamorphic
Quartzite
Quartzite (chiefly SiO2)
Hardness: 7 on Mohs scale; Color: typically white to gray, often with pink/yellow/brown hues due to iron minerals; Luster: Vitreous to dull; Crystal structure: Trigonal (granular texture); Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- 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: typically white to gray, often with pink/yellow/brown hues due to iron minerals; Luster: Vitreous to dull; Crystal structure: Trigonal (granular texture); Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7
Formation & geological history
Quartzite is formed through the metamorphism of quartz sandstone. High heat and pressure cause the quartz grains to recrystallize and fuse together, resulting in a very hard and durable rock. It forms in mountain-building tectonic environments.
Uses & applications
Used as crushed stone in road construction and railway ballast; as dimension stone for flooring, wall coverings, and countertops; and as a source of silica for glass manufacturing.
Geological facts
Quartzite is so tough that it often outlasts the mountains it forms. In a thin section analysis, the original boundaries of the sand grains disappear as they weld into a solid mass of interlocking quartz crystals.
Field identification & locations
Identification in the field: It will scratch glass easily and will not react with acid (unlike marble). Look for a sugary, granular texture that breaks across the grains rather than around them. Found globally in ancient shield regions and mountain belts.
More like this
