sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
Hardness: 2-7 (variable based on clasts); Color: Variable greys, browns, and tans; Luster: Dull/Earthy matrix; Structure: Clastic with rounded pebbles (>2mm); Specific Gravity: 2.1-2.9
- Hardness
- 2-7 (variable based on clasts)
- Color
- Variable greys, browns, and tans
- Luster
- Dull/Earthy matrix
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Physical properties
Hardness: 2-7 (variable based on clasts); Color: Variable greys, browns, and tans; Luster: Dull/Earthy matrix; Structure: Clastic with rounded pebbles (>2mm); Specific Gravity: 2.1-2.9
Formation & geological history
Formed through the lithification of rounded gravel and pebbles in high-energy environments like riverbeds, alluvial fans, or beaches. It can date back to any geological era.
Uses & applications
Used as a low-grade construction aggregate, fill material, and occasionally as decorative dimension stone if the matrix is well-indurated.
Geological facts
Conglomerate is often called 'puddingstone' because it looks like a raisin pudding. It indicates a past environment with strong water currents capable of transporting large particles.
Field identification & locations
Identify by looking for large, rounded stones (called clasts) cemented together in a finer-grained matrix. Often found in ancient river systems or coastal outcrops.
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