Granite

Physical Properties

Hardness: 6-7 on Mohs scale; Color: Pink, white, and translucent; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Specific gravity: 2.63 - 2.75.

Formation & Geological History

Formed from the slow cooling of silica-rich magma deep underground (plutonic). This sample shows high orthoclase feldspar content giving it a pink hue. Most granite dates back to the Precambrian or Paleozoic eras.

Uses & Applications

Extensively used in construction for countertops, floor tiles, and monuments. Coarse pieces are used as landscaping stone or crushed rock.

Geological Facts

Granite is the most common rock found in the Earth's continental crust. The pink color specifically comes from potassium-rich feldspar, and the clear/white translucent portions are quartz.

Field Identification & Locations

Identify by its interlocking mineral crystals and hardness (it cannot be scratched by a steel knife). Look for it in mountainous regions or glacial deposits like riverbeds. It is a 'hard' rock compared to sandstone or limestone.

Identified on: 4/29/2026

Mode: Standard