igneous
Rounded reddish-brown pebble, likely granite or granitic gneiss
Probable biotite-bearing granite (quartz, feldspar, and biotite); exact identification is uncertain from the image
AI-generated identification · may be incorrectRounded, weathered pebble with reddish-brown and gray mottling. Granite is typically Mohs 6–7, with a granular crystalline texture, vitreous quartz, and no prominent cleavage; the wet surface obscures details.
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Physical properties
Rounded, weathered pebble with reddish-brown and gray mottling. Granite is typically Mohs 6–7, with a granular crystalline texture, vitreous quartz, and no prominent cleavage; the wet surface obscures details.
Formation & geological history
If granitic, it crystallized slowly from magma deep in Earth’s crust, commonly billions to hundreds of millions of years ago. Weathering and stream or glacial transport likely rounded the pebble.
Uses & applications
Small pebbles are used decoratively in landscaping and crafts; this specimen appears to have little commercial value.
Geological facts
The smooth, rounded shape indicates abrasion during transport, but does not by itself reveal the rock’s source or age.
Field identification & locations
Look for interlocking grains of quartz and feldspar, possibly with dark mica; a fresh broken surface would help distinguish granite from gneiss or other rocks. Granitic pebbles occur widely in riverbeds and glacial deposits.
