metamorphic
Rounded river pebble, likely weathered quartzite or sandstone
Quartzite (mostly SiO₂), possibly ferruginous sandstone
AI-generated identification · may be incorrectSmall, smooth, tan-gray, opaque pebble with dull earthy luster and apparent fine grain; likely Mohs 6–7 if quartzite, or 5–6 if sandstone. No visible cleavage; rounded by abrasion and weathering.
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Physical properties
Small, smooth, tan-gray, opaque pebble with dull earthy luster and apparent fine grain; likely Mohs 6–7 if quartzite, or 5–6 if sandstone. No visible cleavage; rounded by abrasion and weathering.
Formation & geological history
Formed from quartz-rich sedimentary material, either lithified as sandstone or recrystallized into quartzite during metamorphism; the pebble was later transported and rounded by stream or shoreline erosion. Exact age and identification require testing.
Uses & applications
Primarily a natural collectible or teaching specimen; quartzite can be used as aggregate, road stone, and building material, while sandstone is used for masonry and paving. This individual has negligible commercial value.
Geological facts
The image does not show diagnostic crystals or layering, so a precise identification is uncertain. A steel nail or glass-scratch test, streak, and close inspection of grain boundaries would help distinguish quartzite from softer sandstone.
Field identification & locations
Common in streambeds, glacial deposits, and weathered gravel across quartz-rich terrains. Quartzite should resist scratching by a steel knife and may scratch glass; sandstone commonly feels gritty and may shed grains.
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