Granite

Physical Properties

Hardness: 6-7 on Mohs scale; Color: Mottled gray, white, and pinkish/reddish; Luster: Dull to vitreous; Structure: Phaneritic (coarse-grained crystalline); Cleavage: Indistinct; Specific Gravity: 2.63 to 2.75

Formation & Geological History

Formed through the slow crystallization of magma below Earth's surface (intrusive). They can be formed across various geological ages, notably during orogenic (mountain-building) events.

Uses & Applications

Widely used in construction, countertops, floor tiles, curbing, 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 granite batholith in South Dakota, USA.

Field Identification & Locations

Identify in the field by its 'salt and pepper' appearance and visible interlocking crystals of quartz and feldspar. It is commonly found in mountain ranges and ancient continental shields.

Identified on: 4/15/2026

Mode: Standard