igneous
Granite or granitic rock fragment
Felsic intrusive igneous rock, typically quartz + feldspar + mica; exact species uncertain from the image
AI-generated identification · may be incorrectCoarse, granular texture with pale gray feldspar/quartz and dark biotite or hornblende; generally Mohs 6–7, vitreous to dull luster, massive structure, and no prominent cleavage as a whole rock. The specimen appears weathered and irregular.
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Physical properties
Coarse, granular texture with pale gray feldspar/quartz and dark biotite or hornblende; generally Mohs 6–7, vitreous to dull luster, massive structure, and no prominent cleavage as a whole rock. The specimen appears weathered and irregular.
Formation & geological history
Formed by slow crystallization of silica-rich magma deep in the crust, commonly during Precambrian–Phanerozoic plutonic events; its precise age cannot be determined visually.
Uses & applications
Used as building stone, countertops, monuments, aggregate, and decorative material; small natural fragments have modest collecting interest.
Geological facts
Granite is defined by abundant quartz and alkali feldspar, whereas similar-looking granodiorite contains more plagioclase. A thin section or mineral testing is needed for confident classification.
Field identification & locations
Common worldwide in continental crust and exposed plutons; identify by visible interlocking crystals, light feldspar/quartz, and dark mica or amphibole. Check for reaction with dilute acid and use a hardness test to distinguish carbonate rocks.
