igneous
Weathered granitic rock fragment
Granitoid, likely granodiorite or granite
AI-generated identification · may be incorrectCoarse, irregular fragment with pale gray quartz/feldspar and dark biotite or amphibole; likely Mohs 6–7, vitreous to dull luster, interlocking crystalline texture, and no obvious cleavage as a whole rock. Exact identification is limited by the small, shadowed image.
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Physical properties
Coarse, irregular fragment with pale gray quartz/feldspar and dark biotite or amphibole; likely Mohs 6–7, vitreous to dull luster, interlocking crystalline texture, and no obvious cleavage as a whole rock. Exact identification is limited by the small, shadowed image.
Formation & geological history
An intrusive igneous rock that crystallized slowly from silica-rich magma deep in the crust, commonly during Precambrian to Mesozoic continental pluton formation; surface weathering produced its rough, oxidized appearance.
Uses & applications
Used widely as crushed aggregate, dimension stone, monuments, countertops, and building material; this small weathered piece has negligible commercial value.
Geological facts
Granite-family rocks are mixtures rather than single minerals, typically dominated by quartz, alkali feldspar, plagioclase, and mica or amphibole. Iron-bearing minerals can weather orange-brown.
Field identification & locations
Look for visible interlocking quartz and feldspar grains, a speckled texture, and hardness sufficient to scratch glass; common worldwide in continental mountain belts and exposed plutons. A fresh broken surface and streak or acid tests would improve identification.
