sedimentary
Conglomerate
Conglomerate (Clastic Sedimentary Rock)
Hardness: variable (3-7); Color: tan to gray matrix with multi-colored rounded clasts; Luster: dull; Crystal Structure: non-crystalline matrix; Cleavage: none; SG: 2.5-2.8
- Hardness
- variable (3-7)
- Color
- tan to gray matrix with multi-colored rounded clasts
- Luster
- dull
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Physical properties
Hardness: variable (3-7); Color: tan to gray matrix with multi-colored rounded clasts; Luster: dull; Crystal Structure: non-crystalline matrix; Cleavage: none; SG: 2.5-2.8
Formation & geological history
Formed through the lithification of rounded gravel and boulders, typically in high-energy environments like riverbeds, beaches, or alluvial fans where water rounds the stones.
Uses & applications
Primarily used in the construction industry as coarse aggregate for concrete, road base, or as a decorative building stone.
Geological facts
The key identifier for conglomerate is that the embedded clasts are rounded; if the clasts were angular, the rock would be classified as a breccia.
Field identification & locations
Identify in the field by looking for different-sized rounded pebbles cemented together in a finer-grained matrix. Often found in ancient river channels or glacial deposits.
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