Granite River Rock

Physical Properties

Hardness: 6-7 Mohs; Color: Gray, tan, and white speckled; Luster: Dull/earthy (weathered surface) to vitreous (on fresh breaks); Texture: Phaneritic (visible crystals of quartz, feldspar, and mica); Specific Gravity: 2.63 to 2.75.

Formation & Geological History

Formed from the slow cooling of silica-rich magma deep underground (plutonic). This specific specimen shows rounding and smoothing indicating it was transported and weathered in a high-energy water environment like a river or glacial stream.

Uses & Applications

Used in construction as crushed stone, dimension stone for countertops and monuments, and as decorative landscaping gravel.

Geological Facts

Granite makes up a large portion of the Earth's continental crust. Because it is so hard and resistant to erosion, it often forms the core of many mountain ranges.

Field Identification & Locations

Identify by its 'salt and pepper' appearance and visible interlocking crystals. It will not be scratched by a steel nail. Common globally in crystalline basement rock areas.

Identified on: 4/23/2026

Mode: Standard