igneous
Weathered granite or granitic gneiss
Granite; primarily quartz, alkali feldspar, plagioclase, and mica
AI-generated identification · may be incorrectCoarse-grained, pale gray to tan rock with visible sparkling quartz/feldspar and dark mica; vitreous to pearly luster, no obvious cleavage as a whole, Mohs hardness about 6–7, and specific gravity roughly 2.6–2.7. The image is somewhat blurred, so exact identification is limited.
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Physical properties
Coarse-grained, pale gray to tan rock with visible sparkling quartz/feldspar and dark mica; vitreous to pearly luster, no obvious cleavage as a whole, Mohs hardness about 6–7, and specific gravity roughly 2.6–2.7. The image is somewhat blurred, so exact identification is limited.
Formation & geological history
Granite crystallizes slowly from silica-rich magma deep in continental crust, commonly during Precambrian to Phanerozoic mountain-building events; surface weathering may produce the rounded, brown-stained appearance.
Uses & applications
Widely used as dimension stone, countertops, monuments, paving, aggregate, and decorative material; attractive specimens have modest collector value.
Geological facts
Granite’s interlocking crystals indicate slow cooling underground. Brown coloration commonly reflects oxidation of iron-bearing minerals or surface staining.
Field identification & locations
Identify it by its coarse interlocking texture, quartz-like glassy grains, light feldspar, and scattered dark mica; common worldwide, especially in continental shields and mountain belts.
