sedimentary
Conglomerate
Conglomerative Rudite (SiO2/CaCO3 matrix)
Hardness: 6.5-7 (individual clasts) vs 2-5 (matrix); Color: Tan, brown, or gray matrix with multi-colored rounded pebbles; Luster: Dull/Earthy matrix; Structure: Clastic; Cleavage: None.
- Hardness
- 6
- Luster
- Dull/Earthy matrix
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 (individual clasts) vs 2-5 (matrix); Color: Tan, brown, or gray matrix with multi-colored rounded pebbles; Luster: Dull/Earthy matrix; Structure: Clastic; Cleavage: None.
Formation & geological history
Formed in high-energy environments like fast-flowing rivers or beaches where rounded stones are deposited and later cemented by minerals like calcite or silica over millions of years.
Uses & applications
Primarily used in construction as a coarse aggregate for concrete, road base material, or as decorative building stone in landscaping and internal architecture.
Geological facts
Conglomerates are often dubbed 'pudding stones' due to their resemblance to fruit pudding; they indicate the presence of ancient water currents strong enough to move heavy pebbles.
Field identification & locations
Identify in the field by looking for rounded, water-worn pebbles larger than 2mm embedded in a finer-grained matrix. Commonly found in ancient riverbeds and alluvial fans.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone
Arenite
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary