igneous
Granite
Granite
Hardness: 6-7 on the Mohs scale; Color: Pink, light gray, with black biotite/amphibole flecks; Luster: Dull to vitreous; Structure: Phaneritic (coarse-grained intrusive igneous texture); Composition: Quartz, alkali feldspar (orthoclase/microcline), plagioclase, and mica.
- Hardness
- 6-7 on the Mohs scale
- Color
- Pink, light gray, with black biotite/amphibole flecks
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 on the Mohs scale; Color: Pink, light gray, with black biotite/amphibole flecks; Luster: Dull to vitreous; Structure: Phaneritic (coarse-grained intrusive igneous texture); Composition: Quartz, alkali feldspar (orthoclase/microcline), plagioclase, and mica.
Formation & geological history
Formed by the slow cooling and crystallization of felsic magma deep beneath the Earth's crust in continental plutons and batholiths over millions of years.
Uses & applications
Widely used in construction, road building, dimension stone, countertops, monuments, and as crushed stone for railway ballast and aggregate.
Geological facts
Granite makes up much of the Earth's continental crust. The pink color in this specimen comes from potassium feldspar (orthoclase), while the dark grains are micas like biotite or hornblende.
Field identification & locations
Identified in the field by its coarse-grained interlocking texture with visible quartz and feldspar crystals. Commonly found in mountainous regions, shield areas, and eroded batholiths worldwide.
