igneous
Weathered granitic rock (likely granite or granodiorite)
Granite–granodiorite; mainly quartz, feldspar, and biotite/amphibole
AI-generated identification · may be incorrectCoarse, speckled gray-white rock with dark mafic grains and possible pink feldspar; glassy to dull luster, interlocking crystalline texture, no visible cleavage as a whole, Mohs hardness about 6–7, specific gravity roughly 2.6–2.8.
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Physical properties
Coarse, speckled gray-white rock with dark mafic grains and possible pink feldspar; glassy to dull luster, interlocking crystalline texture, no visible cleavage as a whole, Mohs hardness about 6–7, specific gravity roughly 2.6–2.8.
Formation & geological history
An intrusive igneous rock that crystallized slowly from silica-rich magma several kilometers underground, commonly during Precambrian to Phanerozoic continental mountain-building; surface weathering rounded the specimen.
Uses & applications
Used widely as dimension stone, countertops, paving, monuments, aggregate, and crushed stone; this ordinary rounded piece has little jewelry or commercial collector value.
Geological facts
Granite’s visible grains are individual crystals formed during slow cooling, unlike volcanic rocks with a fine-grained texture.
Field identification & locations
Identify it by its coarse interlocking grains, quartz-gray color, white or pink feldspar, and black biotite or amphibole. Common worldwide, especially in continental shields and mountain belts; a streak, acid, and hardness test can help distinguish it from similar gneiss or diorite.
