Igneous
Granite
Granite (Mainly Quartz SiO2, Feldspar KAlSi3O8, and Mica KAl2(AlSi3O10)(OH)2)
Hardness: 6-7 on Mohs scale; Color: Phaneritic motley of white, gray, and black; Luster: Vitreous to dull; Crystal structure: Coarse-grained granular; Cleavage: None (grains exhibit fracture); Specific Gravity: 2.63 to 2.75
- Hardness
- 6-7 on Mohs scale
- Color
- Phaneritic motley of white, gray, and black
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Phaneritic motley of white, gray, and black; Luster: Vitreous to dull; Crystal structure: Coarse-grained granular; Cleavage: None (grains exhibit fracture); Specific Gravity: 2.63 to 2.75
Formation & geological history
Formed through the slow crystallization of magma below Earth's surface (intrusive). Most granites date back to the Precambrian or Paleozoic eras, forming in continental crust above subduction zones.
Uses & applications
Extensively used as a construction material for countertops, floor tiles, paving stone, monuments, and as aggregate for road base and concrete.
Geological facts
Granite makes up a large portion of the Earth's continental crust. Mount Rushmore is carved into a granite batholith in South Dakota, and the base of the Statue of Liberty is made of granite.
Field identification & locations
Identify in the field by its speckled, 'salt and pepper' appearance and large, visible interlocking crystals of different colors. Commonly found in mountain ranges and glacially drifted areas worldwide.
