igneous
Granite
Granite
Hardness: 6-7 (Mohs scale); Color: Gray, tan, and black mottled appearance; Luster: Vitreous to dull; Crystal structure: Phaneritic (medium to coarse-grained) containing quartz, feldspar, and mica; Specific Gravity: 2.63-2.75
- Hardness
- 6-7 (Mohs scale)
- Color
- Gray, tan, and black mottled appearance
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 (Mohs scale); Color: Gray, tan, and black mottled appearance; Luster: Vitreous to dull; Crystal structure: Phaneritic (medium to coarse-grained) containing quartz, feldspar, and mica; Specific Gravity: 2.63-2.75
Formation & geological history
Formed through the slow crystallization of magma below the Earth's surface (intrusive). Composed mainly of continental crust material, often dating to the Precambrian or Paleozoic eras.
Uses & applications
Extensively used in construction for countertops, floor tiles, paving stone, monuments, and as ballast in infrastructure.
Geological facts
Granite makes up a large portion of the Earth's continental crust and is one of the hardest and most durable substances on the planet. Its name comes from the Latin 'granum', meaning a grain.
Field identification & locations
Identify by its interlocking crystalline texture and lack of layering. Commonly found in mountainous regions or as river-worn cobbles (like this specimen). Check for visible specks of clear quartz and dark biotite mica.
