metamorphic
Rounded river pebble, possibly quartz-rich metamorphic rock
Indeterminate; likely quartzite or weathered quartz-bearing schist
AI-generated identification · may be incorrectGray-brown, fine- to medium-grained, dull to weakly silky luster with a pale gray/white quartz-rich band; apparent hardness about 6–7 Mohs, massive to weakly foliated, with no obvious cleavage. Identification is limited because the specimen is small, rounded, and photographed under indoor lighting.
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Physical properties
Gray-brown, fine- to medium-grained, dull to weakly silky luster with a pale gray/white quartz-rich band; apparent hardness about 6–7 Mohs, massive to weakly foliated, with no obvious cleavage. Identification is limited because the specimen is small, rounded, and photographed under indoor lighting.
Formation & geological history
Likely formed when quartz-rich sediment or sandstone was metamorphosed, then eroded and rounded in a stream or shoreline environment; its precise geological age and locality cannot be determined from the image.
Uses & applications
Suitable mainly as a teaching or collecting specimen; quartzite can be used as aggregate, landscaping stone, and occasionally dimension stone, but this small pebble has negligible commercial use.
Geological facts
Quartzite is commonly harder and more resistant to weathering than its source sandstone, while schist typically shows visible mica flakes and foliation.
Field identification & locations
Look for grains that fracture across rather than around quartz crystals, a glassy streak, and resistance to scratching by steel; a streak test, acid test, and locality information would improve identification. Common in river gravels worldwide.
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