sedimentary

Conglomerate

Sedimentary Conglomerate

Hardness: 6-7 (varies based on clasts); Color: mixed gray, brown, and orange/tan; Luster: dull to earthy; Texture: coarse-grained with rounded clasts; Matrix: typically sand or silt cemented by silica or calcite.

Hardness: 6-7 (varies based on clasts)
Color: mixed gray, brown, and orange/tan
Luster: dull to earthy

Identified July 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in high-energy environments such as riverbeds, alluvial fans, or beaches where water current rounded the rock fragments. These fragments were later buried and cemented over millions of years.

Uses & applications

Primarily used as coarse aggregate in the construction industry for concrete and roadbeds. Some attractive specimens are used for decorative landscaping or minor carving.

Geological facts

Conglomerates are often called 'puddingstones' because the rounded pebbles look like raisins or plums in a pudding. They are useful to geologists for identifying ancient river paths.

Field identification & locations

Identify by looking for rounded, pebble-sized rock fragments bonded together in a finer-grained matrix. They are easily found in old river drainage basins and coastal areas.