Granite

Physical Properties

Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper (white, gray, pink with black specks). Luster: Phaneritic (visible crystals), vitreous to dull. Structure: Granular/Crystalline. Cleavage: None (fractures irregularly). Specific Gravity: 2.63 - 2.75.

Formation & Geological History

Formed through the slow crystallization of magma below Earth's surface (intrusive). Geological ages vary from Precambrian to Cenozoic depending on location. Formed in continental crust at subduction zones or orogenic belts.

Uses & Applications

Extensively used in construction for countertops, floor tiles, paving stones, curbing, monuments, and as aggregate for roads.

Geological Facts

Granite is the most common igneous rock found on Earth's continents. The iconic peaks of Yosemite National Park are made almost entirely of granite. It is extremely durable and resistant to weathering.

Field Identification & Locations

Identify by its 'salt and pepper' appearance and visible interlocking crystals of quartz (clear), feldspar (white/pink), and mica (black/shiny). Found globally in continental shields and mountain ranges. Common in glacial till and riverbeds.

Identified on: 4/24/2026

Mode: Standard