Granite

Physical Properties

Hardness: 6-7 on Mohs scale; Color: Pinkish-grey with black flecks; Luster: Vitreous to dull; Structure: Phaneritic (coarse-grained); Cleavage: None (individual minerals have cleavage, the rock does not)

Formation & Geological History

Formed from the slow crystallization of magma below Earth's surface. It is a plutonic rock that cools over thousands of years, allowing large crystals to grow. Common across all geological eras, especially in continental crust.

Uses & Applications

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

Geological Facts

Granite is the most common igneous rock found on Earth's continental crust and is the signature rock of the continents. Mount Rushmore is carved into a granite batholith.

Field Identification & Locations

Identified by its 'salt and pepper' appearance and visible interlocking crystals of quartz, feldspar, and dark minerals like biotite. It is found in mountain ranges and ancient shield areas.

Identified on: 5/1/2026

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