igneous
Quartz-rich granite or granitic gneiss
Granite; primarily quartz (SiO₂), feldspar, and minor mica
AI-generated identification · may be incorrectLight gray to off-white, coarse granular texture with visible interlocking crystals; typically Mohs 6–7, vitreous quartz luster, feldspar cleavage, and no obvious layering in this fragment. Specific gravity is about 2.6–2.7.
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Physical properties
Light gray to off-white, coarse granular texture with visible interlocking crystals; typically Mohs 6–7, vitreous quartz luster, feldspar cleavage, and no obvious layering in this fragment. Specific gravity is about 2.6–2.7.
Formation & geological history
Likely crystallized slowly from silica-rich magma deep in the continental crust, generally during Precambrian to younger continental mountain-building events; the photograph cannot establish a precise age or distinguish granite from weathered gneiss.
Uses & applications
Widely used as dimension stone, countertops, monuments, paving, aggregate, and landscaping rock; ordinary hand specimens usually have little commercial or collector value.
Geological facts
Quartz-rich granitic rocks commonly weather into sandy, feldspar-rich soil and produce rugged, pale outcrops. The specimen appears weathered and may contain iron staining or altered feldspar.
Field identification & locations
Look for interlocking translucent gray quartz, white or pink feldspar, and scattered black mica; granite is massive, whereas gneiss shows compositional banding. Common worldwide, especially continental shields and mountain belts.
