Granite

Physical Properties

Hardness: 6-7 Mohs; Color: Grey, white, pinkish-tan; Luster: Dull to vitreous; Crystal Structure: Phaneritic (coarse-grained, visible crystals); Specific Gravity: 2.63 - 2.75

Formation & Geological History

Formed from the slow crystallization of magma below the Earth's surface (intrusive). Usually associated with mountain-building events and continental crust dating back hundreds of millions to billions of years.

Uses & Applications

Extensively used in construction for countertops, floor tiles, paving stone, curbing, and monuments due to its durability and aesthetic appeal.

Geological Facts

Granite makes up a large portion of the Earth's continental crust. Mount Rushmore is carved into a granite batholith, and the rock is known for being extremely resistant to weathering.

Field Identification & Locations

Identify in the field by its 'salt and pepper' appearance and visible interlocked crystals of different colors. Commonly found in quarries and mountainous regions worldwide.

Identified on: 4/25/2026

Mode: Standard