sedimentary

Conglomerate

Hardness varies based on matrix and clasts (typically 6-7 if quartz-rich); Color: gray, brown, or tan matrix with multi-colored rounded clasts; Luster: dull/earthy; Texture: clastic/coarse-grained with rounded fragments >2mm.

Color: gray, brown, or tan matrix with multi-colored rounded clasts
Luster: dull/earthy

Identified May 28, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in high-energy environments like riverbeds, alluvial fans, or beaches where water current is strong enough to transport large particles. Over time, these rounded pebbles are buried and cemented together by minerals like calcite or silica. Often dates from the Proterozoic to Cenozoic eras.

Uses & applications

Used primarily as coarse aggregate in the construction industry for concrete and roadbeds. High-quality specimens with colorful jasper or quartz clasts are used as decorative 'pudding stones' for landscaping or lapidary arts.

Geological facts

Commonly known as 'pudding stone' in some regions due to the appearance of 'raisins' or 'fruit' (clasts) inside a 'cake' (matrix). It is an indicator of ancient river systems and shorelines.

Field identification & locations

Identify by looking for rounded rock fragments (clasts) larger than 2mm embedded in a finer-grained matrix. Found in sedimentary basins worldwide, particularly near old mountain ranges or glacial deposits.