metamorphic

River Rock (likely Gneiss or Quartzite)

Metamorphic rock specimen (potentially Foliated Gneiss)

AI-generated identification · may be incorrect

Hardness: 6-7 on Mohs scale; Color: Gray, white with green/yellow algae or moss; Luster: Dull to earthy; Structure: Foliated or massive; Specific Gravity: 2.6-2.9.

Hardness: 6-7 on Mohs scale
Color: Gray, white with green/yellow algae or moss
Luster: Dull to earthy

Identified June 23, 2026More metamorphic →

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Physical properties

Hardness: 6-7 on Mohs scale; Color: Gray, white with green/yellow algae or moss; Luster: Dull to earthy; Structure: Foliated or massive; Specific Gravity: 2.6-2.9.

Formation & geological history

Formed through the metamorphism of pre-existing igneous or sedimentary rocks under high pressure and temperature. This specific specimen has been rounded by fluvial processes (river erosion).

Uses & applications

Commonly used in landscaping, garden decoration, drainage systems, and as aggregate in construction.

Geological facts

River rocks are geological travelers; their smooth, rounded shape is the result of tumbling for miles downstream, a process that can take hundreds or thousands of years.

Field identification & locations

Look for rounded edges and smooth textures. These are commonly found in riverbeds, glacial deposits, and as decorative stones in residential landscaping.