Granite

Physical Properties

Hardness: 6-7 on Mohs scale; Color: Gray, pinkish-orange, and black; Luster: Dull to vitreous; Crystal structure: Phaneritic (visible crystals); Cleavage: None (fractures irregularly).

Formation & Geological History

Formed by the slow crystallization of magma below Earth's surface. These rocks are often millions of years old, associated with continental crust formation and orogenic (mountain-building) events.

Uses & Applications

Extensively used in construction for countertops, floor tiles, paving stone, monuments, and as aggregate for roads.

Geological Facts

Granite makes up a large portion of the Earth's continental crust. Mount Rushmore is carved into a massive granite batholith. It is one of the hardest natural stones available.

Field Identification & Locations

Identify by looking for a coarse-grained texture where individual mineral grains (quartz, feldspar, mica) are visible to the naked eye. Commonly found in mountainous regions or glacial deposits.

Identified on: 5/11/2026

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