igneous
Granite or granitic gneiss
Quartz–feldspar–mica aggregate; possibly banded orthogneiss
AI-generated identification · may be incorrectCoarse-grained, speckled pink, gray, black, and reddish-brown rock with visible interlocking crystals; likely hardness 6–7, vitreous to dull luster, poor cleavage as a whole, and specific gravity about 2.6–2.8.
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Physical properties
Coarse-grained, speckled pink, gray, black, and reddish-brown rock with visible interlocking crystals; likely hardness 6–7, vitreous to dull luster, poor cleavage as a whole, and specific gravity about 2.6–2.8.
Formation & geological history
Probably crystallized slowly from silica-rich magma deep underground, or represents metamorphosed granite; typical ages range from Precambrian to Phanerozoic depending on locality.
Uses & applications
Common granite is widely used as building stone, countertops, monuments, aggregate, and paving; an attractive hand specimen may sell modestly to collectors.
Geological facts
Pink areas are likely potassium feldspar, gray translucent grains quartz, and black flakes or grains biotite and/or amphibole. The image alone cannot reliably distinguish massive granite from weakly foliated gneiss.
Field identification & locations
Identify it by coarse interlocking quartz and feldspar with dark mica, unlike basalt’s fine grain; gneiss may show mineral alignment or banding. Common worldwide in continental crust and exposed mountain belts.
