igneous
Granite
Granitic rock, chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectMedium- to coarse-grained, speckled gray-and-white rock with a granular crystalline texture; hardness about 6–7 Mohs, vitreous quartz luster, negligible cleavage as a whole, and specific gravity around 2.63–2.75.
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Physical properties
Medium- to coarse-grained, speckled gray-and-white rock with a granular crystalline texture; hardness about 6–7 Mohs, vitreous quartz luster, negligible cleavage as a whole, and specific gravity around 2.63–2.75.
Formation & geological history
A felsic intrusive igneous rock formed by slow cooling and crystallization of silica-rich magma deep in continental crust, commonly during Precambrian to Phanerozoic mountain-building events.
Uses & applications
Widely used for countertops, monuments, building stone, paving, aggregate, and polished decorative objects; this rounded specimen has modest collector value.
Geological facts
Its visible grains indicate slow underground cooling; pinkish areas are potassium feldspar, gray translucent grains are quartz, and dark flecks are mafic minerals.
Field identification & locations
Identify it by interlocking visible crystals, abundant light quartz/feldspar, and lack of layering or strong foliation. Common worldwide in continental shields and mountain belts; field specimens are often weathered or glacially rounded.
