Granite

Physical Properties

Hardness: 6-7 Mohs; Color: Mottled black, white, and pinkish-gray; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained, holocrystalline); Cleavage: Dependent on mineral (feldspar: 2 planes, quartz: none); Specific gravity: 2.63-2.75

Formation & Geological History

Formed by the slow crystallization of magma below Earth's surface in continental crustal environments. It is often of Precambrian to Cenozoic age, typically part of large batholiths.

Uses & Applications

Extensively used in construction (countertops, floor tiles, paving stones), monuments, and as crushed stone for road base and aggregate.

Geological Facts

Granite is the most common rock found in the Earth's continental crust. It was used in many of the oldest surviving structures in Egypt, including the pyramids.

Field Identification & Locations

Identify by its interlocking coarse grains of light-colored minerals (quartz and feldspar) and dark minerals (biotite or hornblende). Found in mountainous regions and continental shields like the Canadian Shield or the Appalachians.

Identified on: 5/1/2026

Mode: Standard