sedimentary

Conglomerate

Conglomerate (SiO2 matrix with various inclusions)

AI-generated identification · may be incorrect

Hardness: variable (matrix 3-4, clasts 7); Color: brownish-tan, grey, white; Luster: earthy to dull; Structure: clastic texture with rounded to sub-angular pebbles; Cleavage: none.

Hardness: variable (matrix 3-4, clasts 7)
Color: brownish-tan, grey, white
Luster: earthy to dull

Identified May 14, 2026More sedimentary →

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Physical properties

Hardness: variable (matrix 3-4, clasts 7); Color: brownish-tan, grey, white; Luster: earthy to dull; Structure: clastic texture with rounded to sub-angular pebbles; Cleavage: none.

Formation & geological history

Formed in high-energy environments like riverbeds or alluvial fans where water rounds heavy sediment over thousands of years before burial and lithification.

Uses & applications

Used primarily in the construction industry as coarse aggregate for concrete and road fill; historically used for millstones.

Geological facts

Conglomerates are often referred to as 'puddingstone' because they resemble a fruit pudding. They are key indicators for geologists to locate ancient river systems.

Field identification & locations

Identify in the field by looking for rounded pebbles (clasts) larger than 2mm cemented in a finer-grained matrix. Found globally in ancient sedimentary basins.