igneous
Polished granite
Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectCoarse-grained, mottled pink, gray, white, and black with a polished vitreous-to-dull luster; individual crystals are interlocking and lack cleavage as a whole. Typical hardness is about 6–7 Mohs and specific gravity 2.63–2.75.
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Physical properties
Coarse-grained, mottled pink, gray, white, and black with a polished vitreous-to-dull luster; individual crystals are interlocking and lack cleavage as a whole. Typical hardness is about 6–7 Mohs and specific gravity 2.63–2.75.
Formation & geological history
An intrusive igneous rock formed by slow crystallization of silica-rich magma deep in the crust, commonly during Precambrian to Phanerozoic mountain-building events; the specimen has been rounded and polished by humans.
Uses & applications
Widely used for countertops, monuments, building stone, tiles, aggregate, and landscaping; polished pieces are also sold as decorative stones and desk specimens.
Geological facts
The pink coloration generally comes from potassium feldspar, gray or glassy grains from quartz, and black flecks from biotite or amphibole. The exact variety could be a related granitic rock such as syenite or granodiorite without a thin section or chemical test.
Field identification & locations
Identify it by its visible interlocking grains, pink feldspar, translucent gray quartz, and dark mica/amphibole specks; unlike many marbles, it does not fizz strongly with dilute acid. Common sources include India, Brazil, Scandinavia, Canada, and the United States.
