sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
Hardness: variable (depends on clast type, usually 6-7 for quartz fragments); Color: tan, brown, or grey matrix with multi-colored rounded pebbles; Luster: dull/earthy; Structure: clastic texture with rounded fragments >2mm in diameter.
- Luster
- dull/earthy
Identified More sedimentary →
Explore Conglomerate in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: variable (depends on clast type, usually 6-7 for quartz fragments); Color: tan, brown, or grey matrix with multi-colored rounded pebbles; Luster: dull/earthy; Structure: clastic texture with rounded fragments >2mm in diameter.
Formation & geological history
Formed through the lithification of rounded gravel and pebbles, typically in high-energy environments like river beds, alluvial fans, or beaches where water movement rounds the stones over time.
Uses & applications
Primarily used as a coarse aggregate in the construction industry for concrete and roads; occasionally used as decorative stone in landscaping or interior design.
Geological facts
Conglomerate is often called 'puddingstone' because the rounded stones embedded in the matrix look like raisins in a pudding. It is an indicator of ancient high-energy water systems.
Field identification & locations
Identify by looking for large, rounded rock fragments cemented together in a finer matrix. Common in sedimentary basins worldwide. It differs from breccia, which contains angular fragments.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Cone-in-cone structure (Limestone)
Cone-in-cone structure (Secondary Sedimentary Structure)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary