Granite

Physical Properties

Hardness: 6-7 on Mohs scale; Color: Phaneritic texture with pink, white, and black grains; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Specific gravity: 2.65–2.75

Formation & Geological History

Formed by the slow crystallization of magma below the Earth's surface (intrusive igneous). It can date from the Archean Eon to the Cenozoic era, primarily found in continental crust.

Uses & Applications

Extensively used in construction for countertops, floor tiles, paving stones, 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.

Field Identification & Locations

Identify in the field by its interlocking coarse grains of quartz (glassy), feldspar (opaque/colored), and mica (shiny flakes). Found in mountainous regions and exposed shields.

Identified on: 4/16/2026

Mode: Standard