igneous
Granite
Granite; primarily quartz (SiO₂), feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, light gray rock with visible interlocking crystals, glassy quartz, pale feldspar, and dark mica; Mohs hardness about 6–7, nonmetallic luster, poor cleavage as a rock, and specific gravity around 2.6–2.8.
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Physical properties
Coarse-grained, light gray rock with visible interlocking crystals, glassy quartz, pale feldspar, and dark mica; Mohs hardness about 6–7, nonmetallic luster, poor cleavage as a rock, and specific gravity around 2.6–2.8.
Formation & geological history
A plutonic igneous rock formed when silica-rich magma cooled slowly deep within Earth, allowing large crystals to grow. Most granite formed during Precambrian to Phanerozoic mountain-building events and was later exposed by uplift and erosion.
Uses & applications
Widely used as dimension stone, countertops, monuments, paving, aggregate, and occasionally as polished decorative material; attractive crystal texture gives quality specimens modest collector interest.
Geological facts
The specimen’s rounded shape and weathered surface suggest transport or prolonged surface exposure. Dark specks are likely biotite or amphibole, while bright grains are quartz or feldspar.
Field identification & locations
Identify granite by its visibly interlocking, relatively coarse quartz–feldspar–mica texture and lack of layering or fossils; common worldwide in continental crust, including India, Brazil, Scandinavia, Canada, and the United States.
