Granite

Physical Properties

Hardness: 6-7 on Mohs scale. Color: Gray, white, pink, or reddish. Luster: Vitreous to dull. Crystal structure: Phaneritic (coarse-grained) with visible crystals of quartz, feldspar, and mica.

Formation & Geological History

Formed from the slow crystallization of magma below Earth's surface. It is a plutonic rock that can range from several hundred million to over a billion years old, found in the continental crust.

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 massive granite batholith in the Black Hills of South Dakota.

Field Identification & Locations

Identify by its interlocking 'salt and pepper' appearance of different minerals. It is commonly found in mountainous regions or areas where ancient mountain ranges have eroded away.

Identified on: 4/26/2026

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