Granite Cobble

Physical Properties

Hardness: 6-7 on Mohs scale. Color: Mottled grey, tan, and orange-yellow. Luster: Vitreous to dull. Crystal structure: Phaneritic (visible crystals). Specific gravity: 2.63-2.75.

Formation & Geological History

Formed from the slow cooling of silica-rich magma deep underground (plutonic). This specimen appears water-worn, suggesting transport via river or glacial activity.

Uses & Applications

Commonly used in construction, road base, and landscaping. High-quality slabs are used for countertops and monuments.

Geological Facts

Granite makes up a large portion of the Earth's continental crust. The yellow-orange tint in this specimen likely comes from iron oxide staining or secondary weathering of feldspars.

Field Identification & Locations

Identify in the field by its interlocking crystalline texture and lack of layering. Found globally in mountainous regions and glacial till.

Identified on: 4/28/2026

Mode: Standard