igneous
Granite
Granite, a coarse-grained felsic intrusive igneous rock composed chiefly of quartz, feldspar, and mica
AI-generated identification · may be incorrectGray, speckled, and visibly crystalline with a granular texture; constituent minerals are typically Mohs 6–7 (quartz), with feldspar around 6. Luster ranges from glassy on quartz to pearly on feldspar; crystals are interlocking and lack cleavage as a whole rock.
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Physical properties
Gray, speckled, and visibly crystalline with a granular texture; constituent minerals are typically Mohs 6–7 (quartz), with feldspar around 6. Luster ranges from glassy on quartz to pearly on feldspar; crystals are interlocking and lack cleavage as a whole rock.
Formation & geological history
Likely formed as magma cooled slowly beneath Earth’s surface, allowing crystals to grow. Granite bodies occur in continental crust of many ages, from ancient Precambrian terranes to younger mountain belts.
Uses & applications
Used as building and paving stone, countertops, monuments, aggregate, and decorative stone; this small rough fragment is mainly of educational or collecting interest.
Geological facts
The specimen’s gray, white, and dark mineral grains are consistent with granite, though a photograph cannot confirm its exact rock type.
Field identification & locations
Look for interlocking visible grains of light quartz/feldspar and darker mica or amphibole; common in continental mountain regions worldwide. Estimated value: about $0–$5 for an ordinary hand-sized fragment.
