sedimentary

Conglomerate

Conglomerate (clastic sedimentary rock)

Hardness: variable depending on clasts (usually 6-7 if quartz-rich); Color: reddish-brown matrix with tan/yellow clasts; Luster: dull to earthy; Structure: coarse-grained clastic texture with rounded rock fragments; Cleavage: none.

Hardness: variable depending on clasts (usually 6-7 if quartz-rich)
Color: reddish-brown matrix with tan/yellow clasts
Luster: dull to earthy

Identified June 21, 2026More sedimentary →

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Physical properties

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 action rounds the fragments over time.

Uses & applications

Used as aggregate in construction, decorative stones in landscaping, and occasionally as dimension stone for building interiors.

Geological facts

Conglomerates are often referred to as 'puddingstone' because the rounded pebbles look like raisins or plums inside a pudding. They are key indicators of past water flow and energy levels in ancient environments.

Field identification & locations

Identify by the presence of large, rounded pebbles or clasts (greater than 2mm) cemented within a finer-grained matrix. Look for these in ancient river basins and coastal geological formations.

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