sedimentary

Conglomerate

Hardness: variable (depends on clasts); Color: mixed, usually grays, browns, and tans; Luster: dull/earthy; Texture: clastic with rounded grains larger than 2mm; Cleavage: none.

Hardness: variable (depends on clasts)
Color: mixed, usually grays, browns, and tans
Luster: dull/earthy

Identified June 12, 2026More sedimentary →

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Physical properties

Hardness: variable (depends on clasts); Color: mixed, usually grays, browns, and tans; Luster: dull/earthy; Texture: clastic with rounded grains larger than 2mm; Cleavage: none.

Formation & geological history

Formed by the lithification of rounded gravel and pebbles, typically in high-energy environments like riverbeds, alluvial fans, or beaches where water rounds the stones before burial.

Uses & applications

Primarily used in construction as a coarse aggregate for concrete or as a decorative stone in landscaping. Not typically used in jewelry due to its coarse nature.

Geological facts

Conglomerate is often called 'puddingstone' because its appearance resembles a fruit pudding. It is often confused with breccia, which contains angular rather than rounded fragments.

Field identification & locations

Identify by looking for rounded pebbles (clasts) cemented in a finer-grained matrix. Found globally in ancient riverbeds and basins. Collectors look for unique color combinations or 'monomict' types.