sedimentary

Mixed river gravel (likely alluvial sediment)

Unconsolidated polymictic gravel; rock fragments of varied composition

AI-generated identification · may be incorrect

Pebbles and granules of varied colors and lithologies, mostly angular to rounded, with no single hardness, luster, or crystal structure; fragments may include quartz-rich rocks and dark minerals. Grain sizes range from sand to pebble size.

Identified October 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Water transported and deposited this mixed sediment in a river or stream channel; the source rocks and age cannot be determined from the image. It is unconsolidated, not a single lithified rock.

Uses & applications

Used as aggregate in landscaping, drainage, pathways, and concrete when suitably graded and clean; little jewelry value.

Geological facts

Alluvial gravel commonly combines material eroded from multiple upstream rock types.

Field identification & locations

Look for mixed grain sizes, contrasting rock fragments, and water-worn shapes; angular pieces can reflect short transport or crushing. Common in streambeds and terraces; this loose handful has minimal collector value, typically under $1.