igneous
Granite
Phaneritic Plutonic Rock (primarily Quartz, Feldspar, and Mica/Amphibole)
Hardness: 6-7 on Mohs scale. Color: Tan, white, and black speckles. Luster: Dull to vitreous. Crystal structure: Phaneritic (visible crystals). Cleavage: Varies by mineral component. Specific gravity: 2.63 - 2.75.
- Hardness
- 6-7 on Mohs scale
- Color
- Tan, white, and black speckles
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Tan, white, and black speckles. Luster: Dull to vitreous. Crystal structure: Phaneritic (visible crystals). Cleavage: Varies by mineral component. Specific gravity: 2.63 - 2.75.
Formation & geological history
Formed from the slow crystallization of magma below the Earth's surface. This is a plutonic intrusive rock characteristic of continental crust, often appearing in mountain roots across all geological eras.
Uses & applications
Used extensively in construction for countertops, floor tiles, paving stones, and monuments due to its durability and aesthetic appeal.
Geological facts
Granite makes up a large part of the Earth's continental crust. Mount Rushmore is carved into a massive granite batholith in South Dakota.
Field identification & locations
Identify by looking for visible crystals of multiple colors (salt-and-pepper look). Found globally in mountainous regions and riverbeds as rounded pebbles. Very common in glacial till.
