sedimentary

Jasper Conglomerate

Jasper Conglomerate (SiO2 matrix with varying mineral inclusions)

AI-generated identification · may be incorrect

Hardness: 6.5-7; Color: Mottled red, brown, tan, and cream; Luster: Dull to waxy; Crystal structure: Microcrystalline (matrix); Cleavage: None; Specific gravity: 2.6-2.9.

Hardness: 6
Color: Mottled red, brown, tan, and cream
Luster: Dull to waxy

Identified April 5, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7; Color: Mottled red, brown, tan, and cream; Luster: Dull to waxy; Crystal structure: Microcrystalline (matrix); Cleavage: None; Specific gravity: 2.6-2.9.

Formation & geological history

Formed through the cementation of water-worn pebbles and gravel by silica-rich fluids (jasper) over millions of years. This usually occurs in high-energy riverbeds or beach environments.

Uses & applications

Used primarily as decorative transition stones, for lapidary work (cabochons and beads), and as architectural accents in landscaping.

Geological facts

One of the most famous varieties is the 'Puddingstone' from Michigan and Ontario, which was formed during the Huronian Period over 2 billion years ago.

Field identification & locations

Identify by looking for rounded pebbles (clasts) of different colors fused together in a very hard, fine-grained matrix. Often found in glacial till areas and near the Great Lakes.