igneous
Granite
Phaneritic Felsic Intrusive Rock
Hardness: 6-7 on Mohs scale. Color: Pinkish-red (from Potassium Feldspar), white/gray (Quartz), and black (Biotite/Hornblende). Luster: Vitreous to dull. Crystal structure: Phaneritic (coarse-grained), equigranular. Specific Gravity: 2.63-2.75.
- Hardness
- 6-7 on Mohs scale
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Pinkish-red (from Potassium Feldspar), white/gray (Quartz), and black (Biotite/Hornblende). Luster: Vitreous to dull. Crystal structure: Phaneritic (coarse-grained), equigranular. Specific Gravity: 2.63-2.75.
Formation & geological history
Formed from the slow crystallization of silica-rich magma below the Earth's surface (intrusive). This allows large mineral crystals to grow. Most granites date from the Precambrian to Cenozoic eras.
Uses & applications
Major use in construction (countertops, floor tiles, paving stones), monuments, curbing, and as crushed stone for road base and railroad ballast.
Geological facts
Granite makes up a large portion of the Earth's continental crust. El Capitan in Yosemite National Park is one of the most famous massive granite monoliths in the world.
Field identification & locations
Identify by its interlocking 'salt and pepper' or multi-colored granular appearance with visible crystals. Commonly found in mountainous regions or shield areas like the Canadian Shield. Collectors look for unique colors or large phenocrysts.
