igneous
Granite
Phaneritic Felsic Igneous Rock
Hardness: 6-7 on Mohs scale; Color: grey, white, and tan speckled; Luster: dull to vitreous; Crystal structure: phaneritic (large, visible crystals); Cleavage: none (irregular fracture); Specific gravity: 2.63 - 2.75
- Hardness
- 6-7 on Mohs scale
- Color
- grey, white, and tan speckled
- Luster
- dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale; Color: grey, white, and tan speckled; Luster: dull to vitreous; Crystal structure: phaneritic (large, visible crystals); Cleavage: none (irregular fracture); Specific gravity: 2.63 - 2.75
Formation & geological history
Formed from the slow crystallization of magma below Earth's surface. Can range from hundreds of millions to billions of years old, often found in the cores of mountain ranges.
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. It is one of the hardest natural substances on Earth, and Mount Rushmore is carved into a massive granite batholith.
Field identification & locations
Identify by its interlocking 'salt and pepper' crystalline texture and extreme hardness (it will scratch glass). Commonly found in mountainous regions or areas where ancient bedrock is exposed.
