igneous
Granite
Phaneritic Felsic Igneous Rock (Granite)
Hardness: 6-7 on Mohs scale; Color: Mottled gray, pink, and tan; Luster: Vitreous to dull; Crystal structure: Phaneritic (visible crystals of quartz, feldspar, and mica); Specific gravity: 2.63 to 2.75
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled gray, pink, and tan
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Mottled gray, pink, and tan; Luster: Vitreous to dull; Crystal structure: Phaneritic (visible crystals of quartz, feldspar, and mica); Specific gravity: 2.63 to 2.75
Formation & geological history
Formed by the slow crystallization of magma below Earth's surface. It is a plutonic rock that cools over thousands to millions of years, typically found in continental crust and mountain ranges.
Uses & applications
Extensively used in construction, countertops, floor tiles, paving stones, and as crushed stone for aggregate. Polished specimens are used for monuments and decorative items.
Geological facts
Granite makes up a large portion of the Earth's continental crust. Mount Rushmore is carved into a massive granite batholith in South Dakota.
Field identification & locations
Identify by its salt-and-pepper appearance and visible individual mineral grains. It is very hard and will not be scratched by a steel knife. Common in mountainous regions and riverbeds.
