igneous
Granite
Phaneritic Felsic Igneous Rock
Hardness: 6-7 on Mohs scale; Color: Speckled gray, white, and black; Luster: Dull to vitreous; Structure: Phaneritic (coarse-grained visible crystals); Specific Gravity: 2.63 to 2.75.
- Hardness
- 6-7 on Mohs scale
- Color
- Speckled gray, white, and black
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Speckled gray, white, and black; Luster: Dull to vitreous; Structure: Phaneritic (coarse-grained visible crystals); Specific Gravity: 2.63 to 2.75.
Formation & geological history
Formed through the slow crystallization of magma below Earth's surface (intrusive). Most granite dates to the Precambrian or Paleozoic eras and forms in continental crust above subduction zones.
Uses & applications
Widely used in construction for countertops, floor tiles, paving stones, curbing, and monuments due to its durability and aesthetic appeal.
Geological facts
Granite makes up a large portion of the Earth's continental crust. Mount Rushmore is carved into a granite batholith in the Black Hills of South Dakota.
Field identification & locations
Identify in the field by looking for a 'salt and pepper' appearance with interlocking crystals of quartz, feldspar, and mica. It is found in mountain ranges and continental shields worldwide.
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