sedimentary

Puddingstone (conglomerate)

Lithified polymict conglomerate, with rounded to subrounded pebble clasts in a finer matrix

AI-generated identification · may be incorrect

The specimen appears mottled tan, gray, and dark brown, with contrasting clasts and matrix; mostly opaque and dull to slightly waxy. Individual mineral hardness and composition cannot be determined from the photo; conglomerate has no single crystal structure or Mohs hardness.

Identified September 28, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when gravel-sized fragments were transported, rounded, deposited, and cemented into rock. Its age and exact formation environment cannot be established from appearance alone.

Uses & applications

Primarily collected as a decorative specimen; conglomerate is also used locally as building stone and aggregate.

Geological facts

The varied pebble-like patches are clasts, the defining feature of conglomerate; finer-grained rock with angular fragments is called breccia.

Field identification & locations

Look for distinct pebble-sized fragments cemented together, ideally rounded rather than angular. Similar rocks occur in sedimentary basins worldwide; the pictured specimen is too small to identify a specific locality.