sedimentary

Conglomerate

Hardness: 3-7 (variable based on clasts/cement); Color: Brown, tan, green, or grey; Luster: Dull/Earthy; Structure: Clastic; Cleavage: None; Specific Gravity: 2.1-2.9

Hardness: 3-7 (variable based on clasts/cement)
Color: Brown, tan, green, or grey
Luster: Dull/Earthy

Identified July 15, 2026More sedimentary →

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Physical properties

Hardness: 3-7 (variable based on clasts/cement); Color: Brown, tan, green, or grey; Luster: Dull/Earthy; Structure: Clastic; Cleavage: None; Specific Gravity: 2.1-2.9

Formation & geological history

Formed in high-energy environments like riverbeds or beaches where water currents are strong enough to transport large rounded pebbles, which are later cemented together by finer grains and minerals like silica or calcite.

Uses & applications

Primarily used as a coarse aggregate in the construction industry for concrete and roadbeds; sometimes used as architectural stone or for landscaping.

Geological facts

Conglomerate rocks are sometimes called 'puddingstone' because they look like raisins or nuts in a pudding. They serve as excellent indicators of ancient river systems and coastal environments.

Field identification & locations

Identify by looking for rounded rock fragments (clasts) larger than 2mm embedded in a finer-grained matrix. Found globally in old river basins and mountain runoff zones. Common near current water sources.