igneous
Granite
Granite; predominantly quartz, potassium feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectCoarse-grained, speckled white-gray-black appearance with interlocking crystals; Mohs hardness about 6–7, vitreous to dull luster, no cleavage as a whole, and typical specific gravity 2.63–2.75.
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Physical properties
Coarse-grained, speckled white-gray-black appearance with interlocking crystals; Mohs hardness about 6–7, vitreous to dull luster, no cleavage as a whole, and typical specific gravity 2.63–2.75.
Formation & geological history
A plutonic igneous rock formed when silica-rich magma slowly crystallized deep underground, commonly during Precambrian to Phanerozoic mountain-building events; the exact age cannot be determined from the image.
Uses & applications
Widely used as building stone, countertops, monuments, paving, aggregate, and landscaping material; attractive polished pieces have modest decorative or collecting value.
Geological facts
The visible coarse texture records slow cooling, while dark grains are likely biotite or hornblende and pale grains are feldspar and quartz.
Field identification & locations
Identify it by its visibly interlocking, millimeter-scale crystals and abundant light quartz/feldspar with dark mica or amphibole; common worldwide in continental crust and exposed mountain ranges.
