igneous
Quartz-rich river pebble
Likely quartz-rich granitic rock; mainly quartz (SiO₂), with possible feldspar and mica
AI-generated identification · may be incorrectRounded, tan-brown, and granular with a dull to slightly sparkly surface; visible grains suggest a hardness near 6–7 Mohs. Exact mineral composition and crystal structure cannot be determined from the photo alone.
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Physical properties
Rounded, tan-brown, and granular with a dull to slightly sparkly surface; visible grains suggest a hardness near 6–7 Mohs. Exact mineral composition and crystal structure cannot be determined from the photo alone.
Formation & geological history
Likely weathered from an older quartz-bearing rock and rounded during transport in water; its geological age is unknown.
Uses & applications
Mostly a natural collectible or decorative pebble; comparable quartz-rich rock is also used as aggregate and dimension stone.
Geological facts
The smooth shape and rounded edges are consistent with abrasion during transport, though handling or artificial tumbling can produce a similar appearance.
Field identification & locations
Look for hard, glassy quartz grains and test whether the pebble scratches glass; a fresh broken surface would help distinguish granite from quartzite or another quartz-rich rock. Similar pebbles occur in river and beach deposits worldwide.
