igneous
Granite
Granite (Phaneritic Quartz-Feldspar rock)
Hardness: 6-7 on Mohs scale; Color: Mottled grey, white, and black; Luster: Dull to vitreous; Crystal Structure: Phaneritic (coarse-grained visible crystals); Specific Gravity: 2.63 to 2.75
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled grey, white, and black
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Mottled grey, white, and black; Luster: Dull to vitreous; Crystal Structure: Phaneritic (coarse-grained visible crystals); Specific Gravity: 2.63 to 2.75
Formation & geological history
Formed from the slow crystallization of magma below the Earth's surface (intrusive). Typical ages range from billions of years (Archean) to more recent tectonic events.
Uses & applications
Extensively used in construction for countertops, floor tiles, paving stones, curbing, monuments, and as crushed stone for road base.
Geological facts
Granite makes up a large portion of the Earth's continental crust. Mount Rushmore is carved into a granite batholith. It is one of the hardest and most durable natural stones.
Field identification & locations
Identify by its 'salt and pepper' appearance and visible interlocking crystals of quartz, feldspar, and mica. Commonly found in mountainous regions or glacial till.
