igneous
Granite
Intrusive Phaneritic Felsic Igneous Rock
Hardness: 6-7 Mohs; Color: Pink, gray, black, and white speckled; Luster: Dull to vitreous; Crystal Structure: Coarse-grained phaneritic; Cleavage: None (fractures in minerals); Specific Gravity: 2.63-2.75
- Hardness
- 6-7 Mohs
- Color
- Pink, gray, black, and white speckled
- 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, gray, black, and white speckled; Luster: Dull to vitreous; Crystal Structure: Coarse-grained phaneritic; Cleavage: None (fractures in minerals); Specific Gravity: 2.63-2.75
Formation & geological history
Formed by the slow crystallization of magma below Earth's surface. It is composed primarily of quartz, feldspar, and mica. This intrusive process allows large crystals to grow over millions of years, typically within continental crust.
Uses & applications
Extensively used in construction for countertops, floor tiles, paving stones, curbing, monuments, and as aggregate for roads and foundations.
Geological facts
Granite is one of the oldest and most abundant rocks on Earth, making up a large portion of the continental crust. The word comes from the Latin 'granum', meaning a grain, in reference to its coarse-grained structure.
Field identification & locations
Identify in the field by its interlocking, visible crystals of quartz (clear/gray) and feldspar (pink/white). It is extremely common in mountainous regions and glacial till. Collectors value unique color variations like blue or deep red granite.
