mineral

Polished Ocean Jasper

Orbicular jasper; microcrystalline quartz (SiO₂) with iron-oxide and other mineral inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; dark brown to olive groundmass with cream orbicular patterns, opaque, waxy to glassy luster, no visible cleavage, and conchoidal fracture. The smooth surface indicates polishing.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

A silica-rich volcanic rock formed when mineral-rich fluids filled cavities in ancient rhyolitic lava, producing orbicular patterns during slow alteration. Most recognized material comes from Paleoproterozoic volcanic rocks near the northwest coast of Madagascar, roughly 1.6 billion years old.

Uses & applications

Used as a lapidary stone for cabochons, beads, carvings, and display pieces; it has little industrial value compared with ordinary jasper.

Geological facts

The concentric cream markings are orbicules formed by successive mineral growth around nuclei, commonly involving quartz, feldspar, and iron oxides. “Ocean jasper” is a trade name rather than a single formally defined mineral species.

Field identification & locations

Identify it by its opaque polished surface, hard silica-rich body, and rounded cream, gray, or rust-colored orbs; it does not show the translucency or banding typical of agate. Comparable orbicular jasper also occurs in Mexico, Australia, and elsewhere.