igneous
Granite
Phaneritic plutonic rock (Quartz, Feldspar, Mica)
Hardness: 6-7 Mohs; Color: Pink, gray, white, and black mottled; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Dependent on mineral constituents; Specific Gravity: 2.63-2.75
- Hardness
- 6-7 Mohs
- Color
- Pink, gray, white, and black mottled
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 Mohs; Color: Pink, gray, white, and black mottled; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Dependent on mineral constituents; Specific Gravity: 2.63-2.75
Formation & geological history
Formed through the slow crystallization of silica-rich magma below the Earth's surface. Found in continental crust, often appearing in mountain roots and cratons dating from the Precambrian to Cenozoic eras.
Uses & applications
Extensively used in construction for countertops, floor tiles, paving stones, monuments, and as crushed stone for road base.
Geological facts
Granite makes up a large part of the Earth's continental crust. Unlike oceanic crust which is primarily basalt, continents are 'buoyant' because they are made of less dense granitic rocks.
Field identification & locations
Identify by its interlocking 'salt and pepper' appearance of multicolored crystals (pink potassium feldspar, white plagioclase, glassy quartz, and dark biotite or hornblende). Found globally in mountainous regions.
