igneous
Weathered granite or granitic gneiss
Granite; primarily quartz (SiO₂), feldspar, and biotite/hornblende
AI-generated identification · may be incorrectCoarse, mottled pink-brown and dark texture suggests quartz/feldspar with mafic minerals; typically Mohs 6–7, vitreous to dull luster, interlocking crystals, and no strong cleavage as a whole rock. The rounded shape and dark surface appear weathered or stained.
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Physical properties
Coarse, mottled pink-brown and dark texture suggests quartz/feldspar with mafic minerals; typically Mohs 6–7, vitreous to dull luster, interlocking crystals, and no strong cleavage as a whole rock. The rounded shape and dark surface appear weathered or stained.
Formation & geological history
Granite crystallizes slowly from silica-rich magma deep in the crust, commonly during Precambrian to younger continental mountain-building events; surface rounding likely reflects transport and weathering.
Uses & applications
Used as crushed aggregate, dimension stone, paving, monuments, and countertops; ordinary hand specimens have little commercial value.
Geological facts
Pink tones commonly come from potassium feldspar, while black patches are biotite or amphibole. Strong foliation would favor granitic gneiss rather than granite, but the image alone cannot confirm this.
Field identification & locations
Look for visible interlocking quartz and feldspar grains, hardness sufficient to scratch glass, and no fizz with dilute acid. Common in continental shields, mountain belts, and glacial or river gravels.
