metamorphic
Quartzite
Quartzite (SiO2-rich metamorphic rock)
Hardness: 7 on Mohs scale. Color: Pale orange, tan, peach, or pinkish-yellow with translucent quartz grains. Luster: Vitreous to waxy. Fracture: Conchoidal to irregular, breaking through quartz grains rather than around them.
- Hardness
- 7 on Mohs scale
- Luster
- Vitreous to waxy
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale. Color: Pale orange, tan, peach, or pinkish-yellow with translucent quartz grains. Luster: Vitreous to waxy. Fracture: Conchoidal to irregular, breaking through quartz grains rather than around them.
Formation & geological history
Formed when quartz-rich sandstone is subjected to high heat and pressure during regional or contact metamorphism, recrystallizing the silica grains into a dense, interlocking matrix.
Uses & applications
Used as decorative stone, building material, gravel, and as a raw material for silicon production and quartz countertops.
Geological facts
Unlike sandstone, quartzite breaks across its constituent quartz grains rather than along the cement between them, giving it exceptional toughness and weather resistance.
Field identification & locations
Identified by its high hardness (scratches glass easily) and granular yet fused texture. Found widely in mountainous or ancient shield regions. Collectors value rough landscape pieces for home display.
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