Sedimentary or Metamorphic

Unidentified River Rock or Mudstone

N/A (Generic rock fragment)

AI-generated identification · may be incorrect

Small, worn, grey/brownish, opaque, dull to slightly waxy luster, smooth surface due to tumbling or weathering, possible layering or banding.

Identified June 4, 2026More sedimentary or metamorphic →

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Physical properties

Small, worn, grey/brownish, opaque, dull to slightly waxy luster, smooth surface due to tumbling or weathering, possible layering or banding.

Formation & geological history

Likely formed from consolidated mud or silt (mudstone/siltstone) or low-grade metamorphism (slate/phyllite). Rounded shape indicates transport by water (e.g., river or beach environment).

Uses & applications

Landscaping, aggregate, decorative filler, or casual collecting.

Geological facts

River rocks are common finds and represent a variety of rock types that have been weathered and smoothed by moving water and friction with other rocks over time.

Field identification & locations

Identified by its smooth, rounded edges and lack of distinct crystal structure. Commonly found in riverbeds, lakeshores, or beaches. Tips for collectors: Check for unique banding, fossils, or hardness testing to narrow down the exact rock type.