igneous
Weathered granitic rock
Granite or granodiorite; primarily quartz (SiO₂), feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, speckled gray-tan surface with whitish feldspar, translucent quartz, and dark mica/oxidized minerals; typical hardness is about 6–7 Mohs, with vitreous quartz and generally poor cleavage as a rock.
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Physical properties
Coarse-grained, speckled gray-tan surface with whitish feldspar, translucent quartz, and dark mica/oxidized minerals; typical hardness is about 6–7 Mohs, with vitreous quartz and generally poor cleavage as a rock.
Formation & geological history
Formed by slow cooling of silica-rich magma deep in the continental crust, commonly during Precambrian to Phanerozoic intrusive events; the rounded, altered surface reflects weathering and transport.
Uses & applications
Used widely as building stone, countertops, monuments, aggregate, and landscaping rock; small unattractive fragments generally have little jewelry or collector value.
Geological facts
Granite’s visible crystals formed because magma cooled slowly underground. Brown or rusty patches commonly represent oxidation of iron-bearing biotite or amphibole.
Field identification & locations
Identify it by interlocking visible crystals rather than layers or pores; a glassy quartz component and pink/white feldspar distinguish it from many volcanic rocks. Common worldwide, especially in continental shields and mountain belts.
