sedimentary

Conglomerate

Conglomerate (Clastic Sedimentary Rock)

Hardness varies by clast composition (typically Mohs 6-7 for quartz pebbles), color varies widely including tan, brown, reddish, and gray, luster is dull to vitreous on individual clasts, structure is clastic with rounded to sub-rounded gravel-sized fragments cemented together in a finer-grained matrix, specific gravit…

Identified July 31, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed by the consolidation and cementation of gravel-sized and coarser clasts, typically in high-energy environments like fast-flowing rivers, alluvial fans, or beach zones.

Uses & applications

Used primarily in construction as crushed aggregate for road building and concrete production, and occasionally as decorative facing stone.

Geological facts

Conglomerates are often referred to as 'puddingstone' when the rounded pebbles contrast sharply in color with the surrounding matrix.

Field identification & locations

Easily identified in the field by its characteristic 'gravel-in-cement' appearance consisting of distinct rounded pebbles embedded in a finer matrix.

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Shale (clastic sedimentary rock)

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