igneous
Granite
Phaneritic Felsic Intrusive Igneous Rock
Hardness: 6-7 Mohs; Color: Brownish-tan (weathered), white, gray, and black minerals; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Distinct in feldspars, none in quartz.
- Hardness
- 6-7 Mohs
- Color
- Brownish-tan (weathered), white, gray, and black minerals
- Luster
- Vitreous to dull
Identified More igneous →
Explore Granite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 Mohs; Color: Brownish-tan (weathered), white, gray, and black minerals; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Distinct in feldspars, none in quartz.
Formation & geological history
Formed by the slow crystallization of magma below the Earth's surface (intrusive). The brownish tint suggests oxidation or weathering of iron-bearing minerals like biotite. It is a common constituent of continental crust found in plutons.
Uses & applications
Extensively used in construction for countertops, floor tiles, paving stones, curbing, monument stone, and as crushed stone for road base.
Geological facts
Granite is one of the hardest and most durable common rocks. Because it cools so slowly deep underground, the individual mineral crystals are large enough to see with the naked eye.
Field identification & locations
Identify by its 'salt and pepper' appearance and visible interlocking crystals of quartz and feldspar. To verify in the field, look for a rock that cannot be scratched by a steel knife and contains clear, glassy quartz grains.
