igneous
Granite
Granite; chiefly quartz, plagioclase and/or alkali feldspar, with biotite or hornblende
AI-generated identification · may be incorrectCoarse-grained, light gray with dark mica/hornblende flecks; glassy quartz and pearly feldspar luster, interlocking crystals, no cleavage as a whole. Mohs hardness is about 6–7; specific gravity 2.63–2.75.
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Physical properties
Coarse-grained, light gray with dark mica/hornblende flecks; glassy quartz and pearly feldspar luster, interlocking crystals, no cleavage as a whole. Mohs hardness is about 6–7; specific gravity 2.63–2.75.
Formation & geological history
A plutonic igneous rock crystallized slowly from silica-rich magma deep in the crust, commonly during Precambrian to Phanerozoic mountain-building events. The image appears to show a cut or weathered granite surface.
Uses & applications
Widely used for countertops, monuments, paving, building stone and aggregate; attractive varieties are sold as slabs and architectural stone. Small specimens generally have modest collector value.
Geological facts
Its visible “salt-and-pepper” texture reflects large crystals formed by slow cooling. Dark minerals commonly indicate biotite or amphibole, while translucent grains are quartz.
Field identification & locations
Identify it by coarse interlocking grains, abundant pale feldspar, gray quartz and scattered dark minerals; unlike basalt, it is visibly crystalline and light colored. Common worldwide in continental batholiths, including India, Brazil, Canada and the United States.
