Granite

Physical Properties

Hardness: 6-7 on Mohs scale; Color: Pink, white, and grey mottled appearance; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained) containing quartz, feldspar, and mica; Specific gravity: 2.63 to 2.75.

Formation & Geological History

Formed through the slow crystallization of magma below Earth's surface (intrusive). Most granite was formed during the Precambrian to Cenozoic eras in continental crust environments.

Uses & Applications

Extensively used in construction for countertops, floor tiles, paving stone, monuments, and as crushed stone for road base.

Geological Facts

Granite makes up a large portion of the Earth's continental crust. Mount Rushmore is carved into a granite batholith in the Black Hills of South Dakota.

Field Identification & Locations

Identify in the field by its 'salt and pepper' appearance and visible interlocking crystals. It is found globally in mountainous regions and continental shields like the Canadian Shield.

Identified on: 4/16/2026

Mode: Standard