sedimentary

Puddingstone

Conglomerate

Hardness varies based on clasts and matrix, often 6-7 if quartz-rich; color consists of a light matrix with distinct rounded reddish clasts; coarse-grained.

Identified July 23, 2026More sedimentary →

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Physical properties

Hardness varies based on clasts and matrix, often 6-7 if quartz-rich; color consists of a light matrix with distinct rounded reddish clasts; coarse-grained.

Formation & geological history

Formed in high-energy sedimentary environments like fast-flowing rivers or glacial outwash, where rounded pebbles (clasts) are deposited and later cemented together by finer sediment (matrix).

Uses & applications

Decorative landscaping, polishing, local lapidary arts, and collecting.

Geological facts

Puddingstone is named for its resemblance to traditional plum pudding, with the dark pebbles looking like raisins or plums in a lighter dough.

Field identification & locations

Easily identified by the contrast between the rounded pebbles, often red jasper or quartzite, and the lighter colored matrix. Common in certain glacial deposits and riverbeds.