Granite

Physical Properties

Hardness: 6-7 Mohs; Color: Salt and pepper (gray, white, black); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Specific gravity: 2.63-2.75

Formation & Geological History

Formed from the slow crystallization of magma below Earth's surface. It is an intrusive igneous rock typical of continental crust, often dating back hundreds of millions of years.

Uses & Applications

Extensively used in construction for countertops, floor tiles, paving stones, curbing, and monuments due to its durability.

Geological Facts

Granite is one of the hardest substances in the world. Mount Rushmore is carved into a granite batholith in South Dakota.

Field Identification & Locations

Identify by its visible interlocking crystals of quartz (clear/gray) and feldspar (white/pink). Found worldwide in mountain ranges and Shields. Collectors look for unique mineral inclusions.

Identified on: 5/3/2026

Mode: Standard