mineral

Polished orbicular jasper (likely ocean jasper)

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

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; brown, mustard-yellow, cream, and white patterns; vitreous to waxy luster when polished; cryptocrystalline quartz with no visible cleavage and conchoidal fracture. The rounded shape is tumbled or polished.

Identified August 30, 2026More mineral →

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Physical properties

Formation & geological history

Formed by silica-rich fluids replacing or filling cavities in volcanic rock, with iron oxides producing the red-brown colors and contrasting orbicular inclusions. Ocean jasper is chiefly associated with Miocene volcanic rocks of Madagascar, though similar jaspers occur worldwide.

Uses & applications

Used for cabochons, beads, carvings, worry stones, and decorative objects; valued mainly as a lapidary and collector material rather than an industrial stone.

Geological facts

Orbicular patterns can resemble eyes or rosettes and vary greatly within one deposit. “Ocean jasper” is a trade name, not a formally defined mineral species.

Field identification & locations

Identify by its opaque body, multicolored orbicular or brecciated pattern, glassy polish, and inability to scratch with a steel knife; quartz should scratch ordinary glass. Common sources include Madagascar, Australia, Mexico, and the western United States.