igneous
Granite (weathered cobble)
Granite; chiefly quartz, feldspar, and mica/amphibole
AI-generated identification · may be incorrectCoarse-grained, pale gray to pink rock with black mineral flecks and a granular texture; quartz is Mohs 7, while the whole rock is roughly 6–7. It has a vitreous-to-dull luster, interlocking crystals, and no preferred cleavage as a rock.
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Physical properties
Coarse-grained, pale gray to pink rock with black mineral flecks and a granular texture; quartz is Mohs 7, while the whole rock is roughly 6–7. It has a vitreous-to-dull luster, interlocking crystals, and no preferred cleavage as a rock.
Formation & geological history
An intrusive igneous rock that crystallized slowly from silica-rich magma deep underground, commonly during Precambrian to Mesozoic continental episodes; the rounded shape reflects transport and weathering.
Uses & applications
Widely used as crushed aggregate, building stone, countertops, monuments, and decorative landscaping rock; this ordinary cobble has little jewelry value.
Geological facts
The image shows a rounded, weathered specimen with apparent quartz-rich light areas and dark biotite or amphibole grains. Exact identification would require a fresh surface or thin section because similar granitic rocks include granodiorite and gneiss.
Field identification & locations
Look for visible interlocking quartz and feldspar grains, black mica/amphibole, high hardness, and lack of layering or vesicles; common in continental mountain belts and glacial or river deposits.
