igneous
Biotite Granite
Phaneritic Felsic Igneous Rock
Hardness: 6-7 (Mohs scale); Color: Salt and pepper/grey with black flakes; Luster: Vitreous to pearly; Structure: Phaneritic (visible crystals); Cleavage: Distinct in mica components; Specific gravity: 2.63-2.75
- Hardness
- 6-7 (Mohs scale)
- Color
- Salt and pepper/grey with black flakes
- Luster
- Vitreous to pearly
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Physical properties
Hardness: 6-7 (Mohs scale); Color: Salt and pepper/grey with black flakes; Luster: Vitreous to pearly; Structure: Phaneritic (visible crystals); Cleavage: Distinct in mica components; Specific gravity: 2.63-2.75
Formation & geological history
Formed from the slow cooling and crystallization of magma beneath the Earth's surface (intrusive). Contains various minerals like quartz, feldspar, and mica.
Uses & applications
Extensively used in construction for countertops, floor tiles, paving stones, and memorial monuments due to its durability and aesthetic appeal.
Geological facts
Granite is the primary component of continental crust. It is often radioactive because it contains trace amounts of uranium and thorium contained within accessory minerals.
Field identification & locations
Identify by its coarse-grained texture where individual mineral grains (pink/white feldspar, clear quartz, black biotite) are visible to the naked eye. Found in mountain ranges and ancient shields.
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