igneous
Granite
Granite; chiefly quartz (SiO₂), feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, speckled gray rock with interlocking crystals; quartz gives a glassy luster, feldspar is pale, and mica is dark. Hardness is approximately 6–7 Mohs; no cleavage as a whole, though individual minerals may cleave.
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Physical properties
Coarse-grained, speckled gray rock with interlocking crystals; quartz gives a glassy luster, feldspar is pale, and mica is dark. Hardness is approximately 6–7 Mohs; no cleavage as a whole, though individual minerals may cleave.
Formation & geological history
An intrusive igneous rock formed by slow cooling of silica-rich magma deep within continental crust, generally during Precambrian to Cenozoic plutonic events. The image may also show weathered or finely textured granite surface.
Uses & applications
Widely used for countertops, monuments, paving, building stone, and aggregate; attractive varieties are used as architectural and ornamental stone. Common specimens usually have modest collector value.
Geological facts
Granite’s visible grain records slow underground cooling, while its resistance to abrasion makes it durable in construction. Dark flecks are commonly biotite or hornblende.
Field identification & locations
Identify it by its granular texture and mixture of light quartz/feldspar with dark mica or amphibole; unlike basalt, it is generally lighter and visibly crystalline. Common worldwide, especially in continental mountain belts.
