metamorphic
Quartzite
Quartzite, composed predominantly of recrystallized quartz (SiO₂)
AI-generated identification · may be incorrectPale gray-beige, dull to slightly vitreous, with a rough, granular surface and no obvious cleavage. Quartz hardness is 7 Mohs; the image alone cannot confirm its composition or specific gravity.
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Physical properties
Pale gray-beige, dull to slightly vitreous, with a rough, granular surface and no obvious cleavage. Quartz hardness is 7 Mohs; the image alone cannot confirm its composition or specific gravity.
Formation & geological history
Forms when quartz-rich sandstone is recrystallized under heat and pressure, commonly during regional metamorphism; its age depends on the source rock and metamorphic event.
Uses & applications
Used as crushed aggregate, paving and building stone, and sometimes as decorative stone or carvings.
Geological facts
Quartz grains in well-cemented quartzite interlock during metamorphism, making it very resistant to weathering and often harder to break than its original sandstone.
Field identification & locations
The specimen’s shape and texture are consistent with a weathered rock, but a photo cannot reliably distinguish quartzite from other pale rocks. Check for a hard, glass-scratching surface and fractures that cross grains rather than separating them.
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