igneous
Granite
Granite (Felsic Plutonic Rock / SiO2 + Al2O3)
Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper (white, pink, gray, and black). Luster: Vitreous to dull. Structure: Phaneritic (coarse-grained) crystalline. Specific gravity: 2.63 to 2.75.
- Hardness
- 6-7 on Mohs scale
- Color
- Salt-and-pepper (white, pink, gray, and black)
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper (white, pink, gray, and black). Luster: Vitreous to dull. Structure: Phaneritic (coarse-grained) crystalline. Specific gravity: 2.63 to 2.75.
Formation & geological history
Formed through the slow crystallization of magma below the Earth's surface (intrusive). They can range from Archean to Cenozoic ages and are primarily found in the continental crust (batholiths and plutons).
Uses & applications
Used extensively in construction for countertops, floor tiles, paving stones, and monuments. It is also used as crushed stone (aggregate) for road building and concrete.
Geological facts
Granite is actually harder than marble and is one of the most common rocks in the Earth's continental crust. El Capitan in Yosemite National Park is one of the world's most famous granite monoliths.
Field identification & locations
Identify in the field by its visible interlocking crystals of quartz (clear/gray), feldspar (white/pink), and mica (black/shiny). Common in mountain ranges and shield areas. It will not react with acid, unlike limestone.
