igneous
Granite
Granite
Hardness: 6-7 on Mohs scale. Color: Mottled buff, tan, and dark gray/black. Luster: Dull to phaneritic (visible crystals). Structure: Medium to coarse-grained holocrystalline texture. Composition: High quartz and feldspar content with biotite or hornblende.
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled buff, tan, and dark gray/black
- Luster
- Dull to phaneritic (visible crystals)
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Mottled buff, tan, and dark gray/black. Luster: Dull to phaneritic (visible crystals). Structure: Medium to coarse-grained holocrystalline texture. Composition: High quartz and feldspar content with biotite or hornblende.
Formation & geological history
Formed by the slow crystallization of magma below Earth's surface (intrusive). They are found in the core of mountain ranges and continental crust, often dating back millions to billions of years.
Uses & applications
Widely used in construction for countertops, floor tiles, paving stones, curbing, monuments, and as a decorative architectural stone due to its durability.
Geological facts
Granite makes up a large portion of the Earth's continental crust. Mount Rushmore is carved into a granite batholith. It is one of the hardest and most resistant rocks used by humans.
Field identification & locations
Identify by its interlocking 'salt and pepper' crystalline texture and extreme hardness (cannot be scratched by a steel knife). Common in mountainous regions or glacial deposits.
