metamorphic
Quartzite
Quartzite (SiO2)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: off-white to yellowish-grey with purplish-maroon iron-stained streaks; Luster: vitreous to sugary; Texture: granoblastic, crystalline medium-grained matrix; Cleavage: none.
- Hardness
- 7 on Mohs scale
- Luster
- vitreous to sugary
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Physical properties
Hardness: 7 on Mohs scale; Color: off-white to yellowish-grey with purplish-maroon iron-stained streaks; Luster: vitreous to sugary; Texture: granoblastic, crystalline medium-grained matrix; Cleavage: none.
Formation & geological history
Formed from the regional or contact metamorphism of quartz-rich sandstone under intense heat and pressure, causing the original quartz grains to recrystallize into a interlocking mosaic.
Uses & applications
Used in construction as crushed stone for railway ballast, road bases, decorative stone, and historically for stone tool manufacture.
Geological facts
Quartzite is extremely resistant to chemical weathering and erosion, often forming prominent ridge lines and hill tops in mountainous terrain.
Field identification & locations
Identified by its extreme hardness (scratches glass and steel) and sugary crystalline texture that breaks across quartz grains rather than around them. Commonly found in metamorphic mountain belts worldwide.
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