igneous
Granite
Granite; primarily quartz, potassium feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectCoarse-grained, speckled tan-gray rock with a granular texture and usually vitreous quartz plus pink or cream feldspar; hardness is about 6–7 Mohs, with no prominent cleavage as a whole. Specific gravity is typically 2.63–2.75 and luster is generally dull to slightly crystalline.
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Physical properties
Coarse-grained, speckled tan-gray rock with a granular texture and usually vitreous quartz plus pink or cream feldspar; hardness is about 6–7 Mohs, with no prominent cleavage as a whole. Specific gravity is typically 2.63–2.75 and luster is generally dull to slightly crystalline.
Formation & geological history
An intrusive igneous rock formed when silica-rich magma cooled slowly deep underground, allowing visible crystals to grow; individual samples may range from Precambrian to Phanerozoic age. The image alone cannot establish a precise subtype or age.
Uses & applications
Widely used as dimension stone for countertops, monuments, paving, and construction aggregate; ordinary hand specimens have little commercial value.
Geological facts
Granite’s interlocking crystals make it strong and weather-resistant. Pink coloration commonly reflects potassium feldspar, while dark grains are usually biotite or amphibole.
Field identification & locations
Identify it by visible interlocking grains, quartz-rich gray or glassy patches, feldspar, and dark mica/amphibole; it commonly occurs in continental batholiths and mountain belts worldwide. A more exact identification would require a fresh surface, hand lens, and hardness or acid tests.
