sedimentary

Conglomerate

Lithified, poorly sorted gravel; composition is uncertain from the image

AI-generated identification · may be incorrect

Rounded pebble-sized clasts in a finer gray matrix; likely mixed rock fragments and minerals. Hardness and luster vary with the clasts and cement; no single crystal structure or cleavage.

Identified October 4, 2026More sedimentary →

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Physical properties

Rounded pebble-sized clasts in a finer gray matrix; likely mixed rock fragments and minerals. Hardness and luster vary with the clasts and cement; no single crystal structure or cleavage.

Formation & geological history

Formed when rounded gravel deposited by rivers, beaches, or other energetic water was buried and cemented. Its age cannot be determined from appearance alone.

Uses & applications

Conglomerate is used locally as building or decorative stone and is collected as a sedimentary specimen.

Geological facts

Its rounded clasts indicate transport and abrasion before burial; a rock with mostly angular clasts is instead called breccia.

Field identification & locations

Look for distinct rounded pebbles cemented into a continuous rock matrix. Conglomerates occur in ancient river-channel and shoreline deposits worldwide; a fresh surface can help reveal clast composition.