sedimentary
Puddingstone (specifically Gowganda Tillite or Jasper Conglomerate)
Jasper Conglomerate
Hardness: 6.5-7 (Mohs); Color: Cream/white matrix with red jasper, black chert, and quartzite clasts; Luster: Dull to waxy; Structure: Clastic; Specific Gravity: Approx 2.6-2.7
- Hardness
- 6
- Luster
- Dull to waxy
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Cream/white matrix with red jasper, black chert, and quartzite clasts; Luster: Dull to waxy; Structure: Clastic; Specific Gravity: Approx 2.6-2.7
Formation & geological history
Formed during the Huronian Supergroup (Paleoproterozoic era, approx 2.2-2.4 billion years ago) through glacial deposition and subsequent lithification of river sediments.
Uses & applications
Used primarily for decorative landscaping, jewelry (cabochons), lapidary art, and as geological collectibles.
Geological facts
Legend says that French settlers in Canada named it 'puddingstone' because it reminded them of boiled suet pudding with raisins and berries.
Field identification & locations
Identify by looking for rounded red jasper pebbles embedded in a lighter-colored quartzite matrix. Commonly found as glacial erratics throughout Michigan, Ontario, and the Great Lakes region.
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