Granite

Physical Properties

Hardness: 6-7 Mohs; Color: White/grey background with black specks; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarsegrained visible crystals); Specific Gravity: 2.63-2.75

Formation & Geological History

Formed from the slow crystallization of magma below Earth's surface. It is a plutonic rock found in continental crust and typically dates back from several hundred million to billions of years depending on the location.

Uses & Applications

Extensively used in construction for countertops, floor tiles, paving stone, curbing, and monuments. It is also a popular specimen for basic geological study.

Geological Facts

Granite is the most common igneous rock found on Earth's continents. It makes up the core of many mountain ranges, such as the Sierra Nevada and the Himalayas.

Field Identification & Locations

Identify in the field by its 'salt and pepper' appearance and large visible interlocking grains of quartz, feldspar, and mica. It is extremely common in mountainous regions and riverbeds.

Identified on: 4/16/2026

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