igneous
Likely granite or granitic gneiss
Granite: quartz + feldspar + mica; possibly foliated into gneiss
AI-generated identification · may be incorrectLight gray, coarse-grained, with visible pale feldspar/quartz and darker biotite; vitreous quartz and blocky feldspar, generally Mohs 6–7, no strong cleavage in the whole rock, specific gravity about 2.6–2.8.
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Physical properties
Light gray, coarse-grained, with visible pale feldspar/quartz and darker biotite; vitreous quartz and blocky feldspar, generally Mohs 6–7, no strong cleavage in the whole rock, specific gravity about 2.6–2.8.
Formation & geological history
Crystallized slowly from silica-rich magma deep in the continental crust, commonly during Precambrian to Phanerozoic mountain-building; if gneissic, later subjected to intense heat and pressure.
Uses & applications
Widely used as dimension stone, countertops, monuments, aggregate, and building stone; ordinary hand specimens have little commercial value.
Geological facts
The image resolution and lighting prevent confident separation of granite from weathered gneiss or another feldspar-rich rock.
Field identification & locations
Look for interlocking crystals, glassy gray quartz, white or pink feldspar, and black mica; granite lacks layering, whereas gneiss shows mineral banding. Common worldwide, especially in continental shields and mountain belts.
