Granite

Physical Properties

Hardness: 6-7 on Mohs scale; Color: Mottled gray, white, and black (with some brown staining/weathering in this image); Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained visible crystals); Cleavage: Distinct in feldspars, none in quartz.

Formation & Geological History

Formed through the slow crystallization of magma below Earth's surface (plutonic). It can form at various geological ages, often associated with continental crust formation and orogenic (mountain-building) events.

Uses & Applications

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

Geological Facts

Granite makes up the bulk of the Earth's continental crust. It is one of the hardest and most durable common stones, which is why it has been used for monuments that survive for thousands of years, like the Egyptian Pyramids' casing stones.

Field Identification & Locations

Identify in the field by its 'salt and pepper' appearance and visible interlocking crystals of different colors. It is commonly found in the cores of mountain ranges and shield regions like the Canadian Shield.

Identified on: 4/15/2026

Mode: Standard