igneous
Granite
Granite, a coarse-grained felsic intrusive igneous rock composed mainly of quartz, feldspar, and dark mica or amphibole
AI-generated identification · may be incorrectGray, speckled, and crystalline with interlocking grains and no obvious layering. Typical hardness is about 6–7 Mohs; mineral grains have a vitreous to dull luster, and the rock has no consistent cleavage.
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Physical properties
Gray, speckled, and crystalline with interlocking grains and no obvious layering. Typical hardness is about 6–7 Mohs; mineral grains have a vitreous to dull luster, and the rock has no consistent cleavage.
Formation & geological history
Formed when silica-rich magma cooled slowly underground, allowing visible crystals to grow. Granite bodies occur across many geological ages, from ancient continental crust to younger intrusions.
Uses & applications
Used as building and paving stone, countertops, monuments, and landscaping material; attractive pieces are also collected.
Geological facts
Its visible flecks commonly come from quartz, feldspar, and biotite or hornblende. The specimen appears weathered and rounded, but a photo cannot confirm its exact mineral proportions.
Field identification & locations
Look for interlocking light quartz/feldspar grains mixed with darker minerals; granite commonly occurs in continental plutons and mountain ranges worldwide. Similar-looking rocks, such as diorite or gneiss, may require closer inspection to distinguish.
