igneous
Granite
Intrusive igneous felsic rock
Hardness: 6-7 (Mohs); Color: Pink, red, white, or gray; Luster: Dull to vitreous; Crystal Structure: Phaneritic (coarse-grained); Composition: Quartz, Potassium Feldspar, and Plagioclase.
- Hardness
- 6-7 (Mohs)
- Color
- Pink, red, white, or gray
- Luster
- Dull to vitreous
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: Pink, red, white, or gray; Luster: Dull to vitreous; Crystal Structure: Phaneritic (coarse-grained); Composition: Quartz, Potassium Feldspar, and Plagioclase.
Formation & geological history
Formed by the slow crystallization of magma below Earth's surface. These specimens are likely glacial or fluvial erratics, rounded by transport, and vary in age but are typically millions of years old.
Uses & applications
Commonly used in construction, countertops, monuments, paving stones, and as crushed stone for road base.
Geological facts
Granite makes up a large portion of the Earth's continental crust. The pink/red color in the foreground specimen is specifically caused by a high concentration of potassium feldspar (orthoclase).
Field identification & locations
Identify in the field by its speckled appearance and 'salt and pepper' or pinkish coarse grains. It is extremely common in mountainous regions or areas with glacial deposits. Very durable and scratch-resistant.
