What is Granite?


Granite is a light-colored igneous rock with grains large enough to be visible with the unaided eye. It forms from the slow crystallization of magma below Earth’s surface.

Granite is composed mainly of quartz and feldspar with minor amounts of mica, amphiboles, and other minerals. This mineral composition usually gives granite a red, pink, gray, or white color with dark mineral grains visible throughout the rock.

Granite and Granodiorite FAQ - Golden Gate National Recreation Area (U.S.  National Park Service)
Granite: The specimen above is a typical granite. It is about two inches across. The grain size is coarse enough to allow recognition of the major minerals with the unaided eye or with the help of a hand lens. The pink grains are orthoclase feldspar, and the clear to smoky grains are quartz or muscovite. The black grains can be biotite or hornblende. Numerous other minerals can be present in granite.

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