sedimentary

Chert (Jasper variety)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 Mohs; Color: Brownish-red to ochre; Luster: Waxy to vitreous; Crystal structure: Microcrystalline/cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.9

Hardness: 6
Color: Brownish-red to ochre
Luster: Waxy to vitreous

Identified May 21, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Brownish-red to ochre; Luster: Waxy to vitreous; Crystal structure: Microcrystalline/cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.9

Formation & geological history

Formed through the accumulation of silica-rich microfossils or precipitation from silica-rich fluids in sedimentary basins. This specimen shows water-worn rounding, likely from a fluvial or glacial environment.

Uses & applications

Historical use for stone tools (arrowheads); modern use in lapidary arts, jewelry (cabochons), and decorative landscaping.

Geological facts

Jasper is an opaque variety of chalcedony. In ancient times, it was believed to provide protection and was used extensively in cylinder seals and amulets.

Field identification & locations

Identify by its waxy luster, smooth texture, and inability to be scratched by a steel pocketknife. Most commonly found in riverbeds and gravel pits as stable, weather-resistant pebbles.