metamorphic
Quartzite
Quartzite (primarily SiO2)
Hardness: 7 (Mohs scale); Color: White to pale tan/yellow; Luster: Vitreous to greasy; Structure: Crystalline/Granoblastic; Cleavage: None (conchoidal fracture).
- Hardness
- 7 (Mohs scale)
- Color
- White to pale tan/yellow
- Luster
- Vitreous to greasy
Identified More metamorphic →
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Physical properties
Hardness: 7 (Mohs scale); Color: White to pale tan/yellow; Luster: Vitreous to greasy; Structure: Crystalline/Granoblastic; Cleavage: None (conchoidal fracture).
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under heat and pressure, causing the original quartz grains to recrystallize and fuse together.
Uses & applications
Used in construction as crushed stone, for road ballast, as a dimension stone for flooring and countertops, and sometimes in decorative landscaping.
Geological facts
Quartzite is so tough that it often outlasts its parent rock during erosion, frequently forming the tops of hills and mountain ridges.
Field identification & locations
Identify by its ability to scratch glass and its grainy, sugary texture. It is distinguished from marble by its hardness and lack of reaction to acid. Commonly found in folded mountain belts globally.
