Granite

Physical Properties

Hardness: 6-7 on Mohs scale. Color: Mottled pink (feldspar), grey/clear (quartz), and black (mica). Luster: Vitreous to dull. Structure: Phaneritic (coarse-grained visible crystals). Cleavage: Varies by mineral constituent.

Formation & Geological History

Formed by the slow crystallization of magma below Earth's surface. High in silica and alkali metal oxides. Often billions of years old, typically associated with continental crust formation.

Uses & Applications

Used widely in construction (countertops, floor tiles), monuments, paving stones, and as a decorative stone in landscaping and gravel.

Geological Facts

Granite is the most common rock found in the Earth's continental crust. It is so tough that it makes up the 'roots' of major mountain ranges like the Sierra Nevada.

Field Identification & Locations

Identify by its 'salt and pepper' or multicomponent crystal appearance and hardness (it will not be scratched by a steel knife). Commonly found in glaciated regions as rounded river stones or 'erratics.'

Identified on: 4/19/2026

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