sedimentary

Puddingstone

Conglomerate (Gowganda Formation)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs); Color: Cream/tan matrix with red, brown, and black jasper clasts; Luster: Dull to waxy; Texture: Coarse-grained clastic; Composition: Quartzite matrix with Jasper inclusions.

Hardness: 6
Color: Cream/tan matrix with red, brown, and black jasper clasts
Luster: Dull to waxy

Identified July 20, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Cream/tan matrix with red, brown, and black jasper clasts; Luster: Dull to waxy; Texture: Coarse-grained clastic; Composition: Quartzite matrix with Jasper inclusions.

Formation & geological history

Formed approximately 2.3 billion years ago during the Huronian Glaciation. It is a glacial deposit where river-washed jasper pebbles were cemented into a quartz sand matrix and later metamorphosed.

Uses & applications

Used primarily as decorative stone, in lapidary work for jewelry, and as a popular collector's item for rockhounds in the Great Lakes region.

Geological facts

The name 'Puddingstone' comes from early English settlers who thought the rock resembled boiled suet pudding with raisins or currants (the jasper pebbles).

Field identification & locations

Commonly found on the shores of Lake Huron and throughout Michigan/Ontario. Identified by the distinct contrast between the light matrix and the bright red/dark purple jasper pebbles.