metamorphic
Likely gray quartzite or quartz-rich metamorphic fragment
Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with mica or feldspar
AI-generated identification · may be incorrectGray, opaque, weathered surface with a dull to weakly glassy luster and granular texture; quartzite has Mohs hardness about 7, no cleavage, irregular fracture, and specific gravity near 2.65. The image alone cannot reliably distinguish it from a weathered quartz-rich rock.
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Physical properties
Gray, opaque, weathered surface with a dull to weakly glassy luster and granular texture; quartzite has Mohs hardness about 7, no cleavage, irregular fracture, and specific gravity near 2.65. The image alone cannot reliably distinguish it from a weathered quartz-rich rock.
Formation & geological history
Forms when quartz-rich sandstone is recrystallized during metamorphism, typically during regional mountain-building; age depends on its source formation and may range from Precambrian to recent metamorphic belts.
Uses & applications
Used as durable building stone, aggregate, paving, and decorative material; attractive pieces may be collected, though this small fragment has little commercial value.
Geological facts
Quartzite commonly preserves a sugary, interlocking quartz texture and scratches ordinary glass. Strong layering or abundant visible mica would suggest another metamorphic rock, such as schist or met sandstone.
Field identification & locations
Common in metamorphic terrains worldwide, including the Appalachian, Rocky, and Himalayan regions. Confirm by testing whether it scratches glass and examining a fresh break for fused quartz grains; acid testing is generally uninformative.
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