sedimentary
Conglomerate
Conglomerate (clastic sedimentary rock)
Hardness: 2-7 (variable based on clasts/cement); Color: Brown, tan, with green algae/moss coating; Luster: Dull/Earthy; Structure: Clastic with rounded grains/pebbles; Cleavage: None
- Hardness
- 2-7 (variable based on clasts/cement)
- Color
- Brown, tan, with green algae/moss coating
- Luster
- Dull/Earthy
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Physical properties
Hardness: 2-7 (variable based on clasts/cement); Color: Brown, tan, with green algae/moss coating; Luster: Dull/Earthy; Structure: Clastic with rounded grains/pebbles; Cleavage: None
Formation & geological history
Formed through the lithification of rounded gravel and pebbles in high-energy environments like riverbeds or alluvial fans. This specimen shows significant weathering and biological growth (algae/moss).
Uses & applications
Used primarily in the construction industry as coarse aggregate, building stone, and occasionally for decorative landscaping.
Geological facts
Conglomerates are often referred to as 'puddingstone' in certain regions. Because they consist of rounded pebbles, they indicate that the sediment was transported a long distance by water before being deposited.
Field identification & locations
Identify by looking for distinct, water-worn rounded pebbles cemented within a finer-grained matrix. Often found in old river drainage basins or coastal areas.
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