igneous
Granite
Phaneritic plutonic rock (SiO2 range 70-75%)
Hardness: 6-7 on Mohs scale. Color: Salt and pepper appearance with shades of white, gray, and black. Luster: Vitreous to dull. Crystal structure: Phaneritic (coarse-grained), primarily composed of quartz, feldspar, and mica. Specific gravity: 2.63 to 2.75.
- Hardness
- 6-7 on Mohs scale
- 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 on Mohs scale. Color: Salt and pepper appearance with shades of white, gray, and black. Luster: Vitreous to dull. Crystal structure: Phaneritic (coarse-grained), primarily composed of quartz, feldspar, and mica. Specific gravity: 2.63 to 2.75.
Formation & geological history
Formed from the slow crystallization of magma below Earth's surface. These specific large rounded boulders (tors) are likely the result of spheroidal weathering and glacial transport during the last glacial period.
Uses & applications
Used extensively in construction for countertops, floor tiles, paving stones, and curbstones due to its durability. Also used for monuments and decorative architectural elements.
Geological facts
Granite makes up a large part of the continental crust. The boulders in the image show 'exfoliation' or 'sheeting' weathering, where outer layers of the rock flake off like an onion due to pressure release.
Field identification & locations
Identifiable by its visible interlocking crystals of quartz (clear/gray), feldspar (white/pink), and biotite or hornblende (black). Commonly found in mountain ranges and glaciated terrains.
