igneous
Granite (Porphyritic / Pegmatitic Quartz-Feldspar Rock)
Granite / Granodiorite
Mohs hardness 6 to 7, coarse-grained phaneritic texture with pink/tan orthoclase feldspar, translucent quartz, and minor dark mafic minerals (biotite/hornblende). Vitreous to dull luster depending on wetness/polish. Shows uneven fracture and variable grain sizes.
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Physical properties
Mohs hardness 6 to 7, coarse-grained phaneritic texture with pink/tan orthoclase feldspar, translucent quartz, and minor dark mafic minerals (biotite/hornblende). Vitreous to dull luster depending on wetness/polish. Shows uneven fracture and variable grain sizes.
Formation & geological history
Formed by the slow cooling and crystallization of intrusive felsic magma deep within the Earth's crust (plutonic environment). Often Precambrian to Mesozoic in age depending on regional geology.
Uses & applications
Widely used as construction stone, building facades, countertops, gravel/aggregate, decorative landscaping rocks, and lapidary practice.
Geological facts
Granite makes up a large portion of the continental crust. The distinct pink to reddish tones come from potassium-rich alkali feldspar (orthoclase).
Field identification & locations
Can be identified by its interlocking, visible coarse grains of quartz and feldspar with dark mineral speckles. Common in glacial till, riverbeds, mountain ranges, and gravel beds worldwide.
