sedimentary

Conglomerate

Conglomerate / Lithic Wacke

Hardness: variable (depends on clasts, often 6-7); Color: grey, brown, tan; Luster: earthy to dull; Crystal structure: clastic (non-crystalline); Specific Gravity: 2.1-2.9

Hardness: variable (depends on clasts, often 6-7)
Color: grey, brown, tan
Luster: earthy to dull

Identified May 29, 2026More sedimentary →

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Physical properties

Hardness: variable (depends on clasts, often 6-7); Color: grey, brown, tan; Luster: earthy to dull; Crystal structure: clastic (non-crystalline); Specific Gravity: 2.1-2.9

Formation & geological history

Formed by the lithification of rounded gravel and pebbles, typically in high-energy environments like riverbeds, beaches, or alluvial fans. Geological age varies widely from Precambrian to Cenozoic.

Uses & applications

Used primarily in the construction industry as coarse aggregate for concrete and road building. Occasionally used as ornamental stone if it contains colorful pebbles.

Geological facts

Conglomerate is often called puddingstone because the rounded pebbles look like raisins in a pudding. It is one of the few rocks that indicates the speed and direction of ancient water currents.

Field identification & locations

Identify in the field by looking for rounded, water-worn pebbles larger than 2mm cemented in a finer-grained matrix. Found globally in ancient river systems and shorelines.