Granite

Physical Properties

Hardness: 6-7 on Mohs scale. Color: Mottled pink, white, and gray. Luster: Vitreous to dull. Crystal structure: Phaneritic (coarse-grained). Cleavage: Varies by mineral content. Specific gravity: 2.63 to 2.75.

Formation & Geological History

Formed through the slow crystallization of magma below the Earth's surface (intrusive). Often dates back hundreds of millions to billions of years, formed in continental crust environments.

Uses & Applications

Used extensively in construction for countertops, floor tiles, paving stone, curbing, and monuments. Highly valued for durability and aesthetics.

Geological Facts

Granite is the most common igneous rock found on Earth's surface and makes up a large part of the continental crust. Mount Rushmore is carved into a granite batholith.

Field Identification & Locations

Identify by its 'salt and pepper' appearance and visible interlocking crystals of quartz and feldspar. Commonly found in mountainous regions or shield areas. It will not be scratched by a steel knife.

Identified on: 4/21/2026

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