sedimentary

Conglomerate

Conglomerate Rock

AI-generated identification · may be incorrect

Hardness varies by cementation (typically 6-7 for quartz clasts), yellowish-tan to light brown color matrix with rounded translucent quartz grains and pebbles, grainy and dull luster, clastic sedimentary texture with coarse grain size.

Identified July 25, 2026More sedimentary →

Explore Conglomerate in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed by the compaction and cementation of rounded gravel, pebbles, and sand particles deposited in high-energy aquatic environments such as rivers, beach shores, or alluvial fans over long geological periods.

Uses & applications

Used mainly as low-grade construction aggregate, road base material, fill material, and as an educational geological sample for studying ancient stream channels and depositional environments.

Geological facts

Conglomerates are known as 'puddingstones' in some regions when the pebbles contrast sharply with the matrix color. Their presence in the rock record indicates ancient fast-flowing water currents capable of transporting coarse gravel.

Field identification & locations

Identified by visible, rounded clasts larger than 2 mm embedded in a finer matrix of silt, clay, or silica cement. Commonly found in sedimentary basins, riverbeds, and ancient alluvial deposits globally.