igneous
Granite (Light-colored quartz/feldspar variety)
Granite (composed primarily of Quartz SiO2 and Feldspar KAlSi3O8)
Hardness: 6-7 on Mohs scale. Color: Speckled white, grey, and black. Luster: Vitreous to dull. Crystal structure: Phaneritic (coarse-grained). Cleavage: Varies by mineral content; quartz has none, feldspar has two directions.
- Hardness
- 6-7 on Mohs scale
- Color
- Speckled white, grey, and black
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Speckled white, grey, and black. Luster: Vitreous to dull. Crystal structure: Phaneritic (coarse-grained). Cleavage: Varies by mineral content; quartz has none, feldspar has two directions.
Formation & geological history
Formed through the slow crystallization of magma below Earth's surface (intrusive). This process creates large, visible mineral grains. Geological age varies from Precambrian to Cenozoic.
Uses & applications
Widely used in construction for countertops, floor tiles, paving stone, curbing, and monuments. Also a popular specimen for educational geology kits.
Geological facts
Granite makes up much of the continental crust. It is one of the hardest and most durable natural stones, which is why it has been used since ancient Egypt for colossal statues and pyramids.
Field identification & locations
Identify by its 'salt and pepper' appearance and large interlocking crystals. It is found in mountain ranges and continental shields worldwide. Use a hardness test; it will scratch glass easily.
