Granite

Physical Properties

Hardness: 6-7 (Mohs scale); Color: speckled pink, white, and grey; Luster: vitreous to dull; Crystal structure: phaneritic (coarsegrained) granular; Specific gravity: approx. 2.63 - 2.75.

Formation & Geological History

Formed from the slow subterranean cooling and crystallization of magma rich in silica. This specimen is a water-worn river cobble and could range from hundreds of millions to billions of years old.

Uses & Applications

Primary use in construction (countertops, tiles, paving), monuments, and as crushed stone for road base.

Geological Facts

Granite is the most common igneous rock found at the Earth's surface and makes up a significant portion of the continental crust. The pink color is generally attributed to potassium feldspar.

Field Identification & Locations

Identify by its interlocking 'salt and pepper' appearance of quartz, feldspar, and mica. This rounded shape indicates it was transported and smoothed by water at a river or beach.

Identified on: 4/20/2026

Mode: Standard