sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
Hardness: 6-7 (based on matrix and clasts like quartz); Color: Multicolored with gray matrix; Luster: Dull/Earthy; Structure: Clastic with rounded fragments (>2mm); Cleavage: None.
- Hardness
- 6-7 (based on matrix and clasts like quartz)
- Color
- Multicolored with gray matrix
- Luster
- Dull/Earthy
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Physical properties
Hardness: 6-7 (based on matrix and clasts like quartz); Color: Multicolored with gray matrix; Luster: Dull/Earthy; Structure: Clastic with rounded fragments (>2mm); Cleavage: None.
Formation & geological history
Formed through the lithification of rounded gravel and boulders, typically in high-energy environments like riverbeds or alluvial fans where water rounds the stones over time.
Uses & applications
Used primarily in the construction industry as a coarse aggregate for concrete, road base, and occasionally as decorative building stone.
Geological facts
Conglomerate is often called a 'puddingstone' because it looks like raisins or nuts in a pudding. It is a key indicator of ancient river systems and shorelines.
Field identification & locations
Identify in the field by looking for rounded pebbles (clasts) cemented together in a finer-grained matrix. Found globally in old sedimentary basins and modern river channels.
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