sedimentary
Conglomerate
Conglomerate (Sedimentary Clastic Rock)
Hardness: Variable (depending on clast and matrix composition, usually 6-7 if quartz-rich); Color: Grey, tan, or brown matrix with multicolored clasts; Luster: Dull or earthy; Crystal Structure: Clastic (non-crystalline matrix); Cleavage: None; Specific Gravity: 2.6-2.8
- Color
- Grey, tan, or brown matrix with multicolored clasts
- Luster
- Dull or earthy
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: Variable (depending on clast and matrix composition, usually 6-7 if quartz-rich); Color: Grey, tan, or brown matrix with multicolored clasts; Luster: Dull or earthy; Crystal Structure: Clastic (non-crystalline matrix); Cleavage: None; Specific Gravity: 2.6-2.8
Formation & geological history
Formed through the lithification of rounded gravel and boulders. Usually created in high-energy environments like fast-moving rivers or beaches where water rounds the stones. They range in age from Precambrian to Cenozoic.
Uses & applications
Predominantly used as architectural stone, coarse aggregate in the construction industry for concrete, and occasionally as an ornamental stone in landscaping or interior design.
Geological facts
Conglomerates are like a geological 'time capsule,' often containing different types of rocks from many different upstream sources. On Mars, the Curiosity rover discovered conglomerate outcrops, proving the existence of ancient riverbeds on the Red Planet.
Field identification & locations
Identify in the field by looking for rounded, water-worn pebbles larger than 2mm embedded in a finer-grained matrix. Found globally in ancient riverbeds, alluvial fans, and coastal regions. Collectors look for 'puddingstone' varieties with contrasting colors.
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 (Quartz-rich)
Arenite (SiO2)
sedimentary
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
sedimentary