igneous
Granite
Granite (Mainly SiO2 and Al2O3)
Hardness: 6-7 on Mohs scale. Color: Mottled white, gray, and tan. Luster: Vitreous to dull. Structure: Phaneritic (coarse-grained). Cleavage: Varies by mineral constituent. Specific gravity: 2.63 to 2.75.
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled white, gray, and tan
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Mottled white, gray, and tan. Luster: Vitreous to dull. Structure: Phaneritic (coarse-grained). Cleavage: Varies by mineral constituent. Specific gravity: 2.63 to 2.75.
Formation & geological history
Formed from the slow crystallization of silica-rich magma beneath the Earth's surface (intrusive). They can be hundreds of millions to billions of years old, found mostly in continental crust.
Uses & applications
Extensively used in construction for countertops, floor tiles, paving stones, and monuments due to its durability and resistance to weathering.
Geological facts
Granite makes up a large part of the Earth's continental crust and is one of the hardest natural substances in the world. Mount Rushmore is carved into a granite batholith.
Field identification & locations
Identify by its 'salt and pepper' appearance and visible crystals of quartz, feldspar, and mica. Commonly found in mountain ranges and riverbeds. It will not react with acid unlike limestone.
