sedimentary

Gowganda Tillite (Puddingstone)

Gowganda Formation Conglomerate

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs); Color: Dark grey to greenish matrix with pink to red clasts; Luster: Dull to earthy; Structure: Clastic/Rudaceous; Cleavage: None; SG: 2.6-2.8

Hardness: 6-7 (Mohs)
Color: Dark grey to greenish matrix with pink to red clasts
Luster: Dull to earthy

Identified June 23, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs); Color: Dark grey to greenish matrix with pink to red clasts; Luster: Dull to earthy; Structure: Clastic/Rudaceous; Cleavage: None; SG: 2.6-2.8

Formation & geological history

Formed during the Huronian glaciation (approx. 2.3 billion years ago) as glacial till or outwash that was subsequently lithified into conglomerate.

Uses & applications

Used primarily as decorative stone, lapidary specimens, and as a geological indicator for glacial history in North America.

Geological facts

The Gowganda Formation is part of the oldest known widespread ice age in Earth's history. It is often referred to as 'Puddingstone' because the red jasper or feldspar clasts look like raisins in a pudding.

Field identification & locations

Identify by looking for distinct pink feldspar or red jasper fragments embedded in a fine-grained, dark greenish-grey matrix. Commonly found around Lake Huron and throughout Northern Ontario/Michigan.