mineral

Polished orbicular jasper (likely ocean jasper)

Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and other mineral inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; yellow, cream, gray, and reddish-brown orbicular pattern; waxy to glassy luster; opaque to translucent; no obvious cleavage; dense, fine-grained cryptocrystalline structure.

Identified September 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids replace volcanic rock and preserve rounded spherulitic or orb-like inclusions, often with iron staining. Classic ocean jasper formed in Miocene volcanic rocks near Madagascar, though similar orbicular jasper occurs elsewhere.

Uses & applications

Used as a tumbled stone, cabochon, carving material, and lapidary collectible; too small and variable for major construction use.

Geological facts

The photographed piece is polished and appears to be a small cabochon or tumbled stone. “Ocean jasper” is a trade name rather than a single formally defined mineral species.

Field identification & locations

Identify by its opaque chalcedony body, hardness, curved fracture, and orbicular patterns; it should not scratch easily with steel. Common sources include Madagascar, Mexico, Oregon, and Australia.