sedimentary

Conglomerate

Clastic Sedimentary Conglomerate (SiO2, CaCO3, etc.)

AI-generated identification · may be incorrect

Hardness: variable (matrix 3-7, clasts 6-7); Color: tan, grey, or brown matrix with multicolored rounded clasts; Luster: dull/earthy matrix; Crystal structure: none (clastic); Cleavage: none; Specific gravity: 2.3 - 2.8

Hardness: variable (matrix 3-7, clasts 6-7)
Color: tan, grey, or brown matrix with multicolored rounded clasts
Luster: dull/earthy matrix

Identified March 26, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in high-energy environments like riverbeds, alluvial fans, or beaches where water rounds the stones. Large clasts are deposited and later cemented by minerals like silica, calcite, or iron oxide during lithification.

Uses & applications

Used in the construction industry as coarse aggregate for concrete and roadbeds; some colorful varieties are used as decorative stone or for landscaping.

Geological facts

Conglomerate is often called 'puddingstone' due to its resemblance to fruit cake or Christmas pudding. It records the historical path and speed of ancient water systems.

Field identification & locations

Identify in the field by looking for rounded, smooth pebbles (clasts) larger than 2mm embedded in a finer-grained matrix. Often found in ancient river basins and mountain foot-slopes.