igneous
Quartz-rich granite pebble
Granite, composed chiefly of quartz (SiO₂), feldspar, and minor dark mica or amphibole
AI-generated identification · may be incorrectCoarse crystalline, mottled gray-purple and white with scattered dark grains; vitreous quartz and feldspar have Mohs hardness about 6–7, with no consistent cleavage in the whole rock. The rounded surface appears naturally water-worn or tumbled.
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Physical properties
Coarse crystalline, mottled gray-purple and white with scattered dark grains; vitreous quartz and feldspar have Mohs hardness about 6–7, with no consistent cleavage in the whole rock. The rounded surface appears naturally water-worn or tumbled.
Formation & geological history
Granite crystallizes slowly from silica-rich magma deep in the crust, generally over geologic timescales of millions of years; the pebble was later rounded by transport or abrasion. Its exact age and source cannot be determined from the image.
Uses & applications
Common granite is used as dimension stone, paving, aggregate, and landscaping material; this small pebble is mainly suitable for collecting or decoration.
Geological facts
The visible pale, translucent-looking grains and darker flecks are consistent with quartz, feldspar, and mafic minerals, though a photograph cannot confirm the mineral identification.
Field identification & locations
Look for interlocking grains and a speckled appearance rather than sedimentary layering or foliation; granite pebbles occur in river, beach, and glacial deposits worldwide.
