sedimentary
Conglomerate
Clastic Sedimentary Rock (Conglomerate)
Hardness: variable (depends on clasts, often 5-7); Color: brown, tan, gray; Luster: dull/earthy; Texture: coarse-grained with rounded clasts larger than 2mm; Cleavage: none.
- Hardness
- variable (depends on clasts, often 5-7)
- Color
- brown, tan, gray
- Luster
- dull/earthy
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Physical properties
Hardness: variable (depends on clasts, often 5-7); Color: brown, tan, gray; Luster: dull/earthy; Texture: coarse-grained with rounded clasts larger than 2mm; Cleavage: none.
Formation & geological history
Forms through the lithification of rounded gravel and boulders, typically in high-energy environments like riverbeds, alluvial fans, or mountain shorelines where water rounds the stones before they are buried.
Uses & applications
Used primarily in the construction industry as coarse aggregate for concrete or as fill material; occasionally used as a decorative stone in landscaping or interior design when polished.
Geological facts
Conglomerate rocks are essentially a 'record' of ancient river systems and shorelines. They have even been discovered on Mars, providing evidence of past flowing water on the Martian surface.
Field identification & locations
Identified by large, rounded rock fragments (clasts) cemented together in a finer-grained matrix. Look for it in areas of ancient uplift or near modern fast-moving water sources.
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