Granite

Physical Properties

Hardness: 6-7 on Mohs scale; Color: Mottled pink, white, gray, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Dependent on individual mineral grains; Specific gravity: 2.63 to 2.75

Formation & Geological History

Formed from the slow crystallization of magma below Earth's surface. This specimen appears to be a water-worn or weathered fragment of plutonic rock, typically dating from various prehistoric geological periods depending on the regional batholith.

Uses & Applications

Used widely in construction for countertops, floor tiles, paving stone, curbing, and monuments. Also used as crushed stone for road base and aggregate.

Geological Facts

Granite makes up a large portion of the Earth's continental crust. It is one of the hardest substances in the world, second only to diamonds and some other minerals, making it incredibly durable over millennia.

Field Identification & Locations

Identify in the field by its 'salt and pepper' appearance and visible interlocking crystals of quartz, feldspar, and mica. It is found in abundance in mountainous regions and continental shields. For collectors, look for unusually large crystals or rare mineral inclusions.

Identified on: 4/22/2026

Mode: Standard