igneous
Weathered granite
Granite; chiefly quartz, feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, mottled tan-gray rock with visible interlocking feldspar and darker mafic minerals; hardness about 6–7 Mohs, vitreous to dull luster, no cleavage as a whole, and typical specific gravity 2.6–2.7.
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Physical properties
Coarse-grained, mottled tan-gray rock with visible interlocking feldspar and darker mafic minerals; hardness about 6–7 Mohs, vitreous to dull luster, no cleavage as a whole, and typical specific gravity 2.6–2.7.
Formation & geological history
Forms when silica-rich magma slowly crystallizes deep underground, generally in Precambrian to Phanerozoic continental crust; the surface weathering has rounded and stained this specimen.
Uses & applications
Used widely as dimension stone, countertops, paving, monuments, aggregate, and landscaping material; ordinary pieces have little jewelry value.
Geological facts
Granite’s visible crystals record slow cooling, while iron oxidation commonly produces the brown weathering colors seen here.
Field identification & locations
Identify it by its granular texture and scattered light feldspar, translucent-gray quartz, and dark mica or amphibole; common worldwide in continental mountain belts and exposed plutons.
