sedimentary

Jasper Pebble

Microcrystalline Quartz (SiO2)

Hardness of 6.5-7 on the Mohs scale, opaque brown color, dull to waxy luster, microcrystalline or cryptocrystalline crystal structure, conchoidal fracture, specific gravity of 2.58-2.91.

Identified August 5, 2026More sedimentary →

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Physical properties

Hardness of 6.5-7 on the Mohs scale, opaque brown color, dull to waxy luster, microcrystalline or cryptocrystalline crystal structure, conchoidal fracture, specific gravity of 2.58-2.91.

Formation & geological history

Formed through the silification of sedimentary or volcanic deposits where silica-rich fluids precipitate microcrystalline quartz in pore spaces or fractures, shaped into a pebble by water tumbling in a river or coastal environment.

Uses & applications

Used for lapidary work, ornamental carvings, cabochons, jewelry making, and collected as a natural specimen.

Geological facts

Jasper is an aggregate of microgranular quartz and/or chalcedony and other mineral phases. Its rich brown and earthy tones come from iron oxide and hydroxide impurities trapped during formation.

Field identification & locations

Found widely in stream beds, gravel bars, and beaches. Identify by its high hardness (scratches glass), opaque appearance, smooth water-worn surface, and lack of visible crystal grains.