igneous
Polished granite or granitic gneiss pebble
Granite; chiefly quartz, feldspar, and mica/amphibole
AI-generated identification · may be incorrectLight gray, rounded, and naturally tumbled or lightly polished, with visible pale feldspar/quartz and dark mineral flecks; typically granular, nonfoliated, Mohs hardness about 6–7, vitreous to dull luster, and no prominent cleavage as a whole rock.
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Physical properties
Light gray, rounded, and naturally tumbled or lightly polished, with visible pale feldspar/quartz and dark mineral flecks; typically granular, nonfoliated, Mohs hardness about 6–7, vitreous to dull luster, and no prominent cleavage as a whole rock.
Formation & geological history
Formed by slow crystallization of silica-rich magma deep in the crust, commonly during Precambrian to Phanerozoic continental tectonic events; its rounded shape likely results from river or glacial abrasion.
Uses & applications
Used widely as building stone, countertops, monuments, aggregate, and landscaping rock; attractive hand specimens generally have modest decorative value.
Geological facts
Granite’s interlocking crystals make it durable and resistant to weathering, while quartz and feldspar proportions produce its pale appearance.
Field identification & locations
Identify it by its coarse interlocking texture, mixed light and dark minerals, and lack of layering; common worldwide, especially in continental mountain belts and glacial deposits. Exact identification from a photo is limited because the specimen could also be a pale gneiss or other granitoid.
