Rock Identifier

igneous, sedimentary, and metamorphic mix

Mixed Gravel and Pebbles

Polylithic Alluvial Aggregate

AI-generated identification · may be incorrect

Hardness varies from 3 to 7 on the Mohs scale depending on the mineral content; colors include various shades of gray, brown, tan, pink, and white; luster ranges from dull to vitreous; heterogeneous crystal structures.

Identified July 30, 2026More igneous, sedimentary, and metamorphic mix →

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Physical properties

Hardness varies from 3 to 7 on the Mohs scale depending on the mineral content; colors include various shades of gray, brown, tan, pink, and white; luster ranges from dull to vitreous; heterogeneous crystal structures.

Formation & geological history

Formed through the weathering, erosion, transportation, and deposition of various parent rocks by water, ice, or wind, often found in riverbeds, glacial tills, and beaches over varying geological timescales.

Uses & applications

Used primarily in construction for concrete aggregate, road base, landscaping, and drainage.

Geological facts

Such collections often contain a diverse geological history representing multiple rock types from a local watershed.

Field identification & locations

Identified by a mix of rounded or sub-rounded small stones of varying compositions, commonly found in riverbanks, driveways, and garden beds.

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Other igneous, sedimentary, and metamorphic mix specimens

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Igneous, Sedimentary, and Metamorphic mix

Pebble Gravel Mix (Quartzite, Basalt, Chert) (Alluvial River Gravel / Aggregate Clasts) — sedimentary

Pebble Gravel Mix (Quartzite, Basalt, Chert)

Alluvial River Gravel / Aggregate Clasts

Quartz Pebble (Silicon Dioxide (SiO2)) — mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Magnetite / Hematite mix (Magnetite (Fe3O4) and Hematite (Fe2O3)) — mineral

Magnetite / Hematite mix

Magnetite (Fe3O4) and Hematite (Fe2O3)

Gravel / Crushed Stone (Aggregate (mixed mineral rock fragments)) — sedimentary

Gravel / Crushed Stone

Aggregate (mixed mineral rock fragments)

Exposed aggregate concrete (stone-chip surface) (Portland-cement concrete containing natural aggregate; not a natural rock) — sedimentary

Exposed aggregate concrete (stone-chip surface)

Portland-cement concrete containing natural aggregate; not a natural rock