igneous
Weathered granite (likely granitic gneiss)
Granite; primarily quartz, feldspar, and biotite/hornblende
AI-generated identification · may be incorrectHardness about 6–7 Mohs; pink-gray, coarse crystalline, and granular with a dull to slightly vitreous luster. The mottled appearance reflects pink potassium feldspar, pale quartz, and dark mafic minerals; visible pits may indicate weathering.
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Physical properties
Hardness about 6–7 Mohs; pink-gray, coarse crystalline, and granular with a dull to slightly vitreous luster. The mottled appearance reflects pink potassium feldspar, pale quartz, and dark mafic minerals; visible pits may indicate weathering.
Formation & geological history
Formed when silica-rich magma slowly cooled underground, commonly during Precambrian to younger continental-crust events; surface weathering rounded and darkened the specimen.
Uses & applications
Widely used as building stone, countertops, monuments, aggregate, and landscaping rock; this small weathered piece has mainly educational or modest collecting value.
Geological facts
Pink coloration commonly comes from potassium feldspar, while black patches are biotite or amphibole. If foliation or banding is present, it may technically be granitic gneiss rather than granite.
Field identification & locations
Look for interlocking crystals, pink feldspar, gray translucent quartz, and scattered black minerals; granite is common in continental shields and mountain belts worldwide. A scratch test, streak test, and fresh broken surface would improve identification.
