igneous
Granite
Coarse-grained felsic intrusive igneous rock; primarily quartz, alkali feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectTypically hardness 6–7 Mohs, light gray to white with black mica or amphibole, granular texture, and a vitreous-to-dull luster. Crystals are interlocking and visible; cleavage belongs to the individual minerals rather than the rock.
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Physical properties
Typically hardness 6–7 Mohs, light gray to white with black mica or amphibole, granular texture, and a vitreous-to-dull luster. Crystals are interlocking and visible; cleavage belongs to the individual minerals rather than the rock.
Formation & geological history
Forms when silica-rich magma cools slowly deep within continental crust, producing large crystals; individual bodies range from Precambrian to Cenozoic ages. The rounded specimen is likely naturally weathered or human-shaped.
Uses & applications
Widely used as dimension stone, countertops, monuments, paving, aggregate, and landscaping material; polished pieces are also collected as decorative specimens.
Geological facts
Its black flakes are commonly biotite mica, while the glassy grains are quartz and the white-to-pink grains are feldspar. Compositionally similar rocks may be called granodiorite when plagioclase predominates.
Field identification & locations
Identify it by its coarse, interlocking texture and quartz–feldspar–black mica assemblage; unlike basalt, it is pale and visibly crystalline. Common worldwide in continental mountain belts, including the Sierra Nevada, New England, Scandinavia, and India.
