sedimentary
Conglomerate
Conglomerate
Hardness: 2-7 (variable based on clasts and matrix); Color: Mixed greys, tans, and browns; Luster: Dull/Earthy; Structure: Clastic with rounded pebbles (>2mm) embedded in a finer matrix.
- Hardness
- 2-7 (variable based on clasts and matrix)
- Color
- Mixed greys, tans, and browns
- Luster
- Dull/Earthy
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Physical properties
Hardness: 2-7 (variable based on clasts and matrix); Color: Mixed greys, tans, and browns; Luster: Dull/Earthy; Structure: Clastic with rounded pebbles (>2mm) embedded in a finer matrix.
Formation & geological history
Formed through the lithification of rounded gravel and sand deposited in high-energy environments like riverbeds, alluvial fans, or beaches. It can range from millions to hundreds of millions of years old.
Uses & applications
Used primarily as low-grade construction aggregate, fill material, and occasionally as decorative dimensional stone if the matrix is well-cemented and colorful.
Geological facts
Conglomerate is often nicknamed 'puddingstone' because the rounded pebbles look like raisins or plums in a pudding. It indicates a past environment with rapidly flowing water.
Field identification & locations
Identify in the field by looking for rounded, water-worn stones fused together by a natural mineral cement (often silica, calcite, or iron oxide). Common in sedimentary basins worldwide.
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