igneous
Weathered granite (likely pink biotite granite)
Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectCoarse-grained, speckled pink-gray rock with interlocking crystals; quartz has glassy luster, feldspar is pale pink/white, and dark minerals are black-gray. Mohs hardness is about 6–7; no prominent cleavage as a rock, though feldspar crystals cleave; specific gravity is approximately 2.6–2.7.
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Physical properties
Coarse-grained, speckled pink-gray rock with interlocking crystals; quartz has glassy luster, feldspar is pale pink/white, and dark minerals are black-gray. Mohs hardness is about 6–7; no prominent cleavage as a rock, though feldspar crystals cleave; specific gravity is approximately 2.6–2.7.
Formation & geological history
An intrusive igneous rock crystallized slowly from silica-rich magma deep in the continental crust, commonly during Precambrian to Mesozoic mountain-building events. Surface exposure results from uplift, erosion, and weathering.
Uses & applications
Widely used as dimension stone, paving, monuments, curbing, countertops, crushed aggregate, and landscaping rock; attractive polished slabs may have commercial value.
Geological facts
Pink coloration generally reflects potassium feldspar, while gray grains are quartz and dark flecks are biotite or amphibole. The surface shows lichen and weathering rather than mineralization.
Field identification & locations
Common in continental mountain belts and shields worldwide, including the United States, Canada, Brazil, India, and Scandinavia. Identify it by its visible interlocking quartz-feldspar crystals and granular texture; distinguish it from gneiss by the lack of strong mineral banding.
