igneous
Granite
Felsic intrusive igneous rock
Hardness: 6-7 on Mohs scale; Color: Pink, gray, white, and black mottled; Luster: Vitreous to dull; Structure: Phaneritic (coarse-grained); Composition: Quartz, Alkali Feldspar, and Plagioclase.
- Hardness
- 6-7 on Mohs scale
- Color
- Pink, gray, white, and black mottled
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Pink, gray, white, and black mottled; Luster: Vitreous to dull; Structure: Phaneritic (coarse-grained); Composition: Quartz, Alkali Feldspar, and Plagioclase.
Formation & geological history
Formed from the slow crystallization of magma below Earth's surface. This specimen appears to be a water-worn or weathered pebble, likely millions of years old, originating from a plutonic continental crust environment.
Uses & applications
Used extensively in construction for countertops, floor tiles, paving stones, and monuments due to its durability. Small pebbles are often used in landscaping or as aquarium gravel.
Geological facts
Granite makes up much of the Earth's continental crust. The pinkish hue in this specimen is caused by the presence of potassium feldspar (orthoclase). It is one of the hardest and most durable common rocks.
Field identification & locations
Identify in the field by its 'salt and pepper' appearance and visible interlocking crystals of quartz and feldspar. It is found globally in mountainous regions and glacial deposits.
