mineral

Polished ocean jasper (orbicular jasper)

Microcrystalline quartz (SiO₂) with hematite/goethite and other alteration minerals

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; rounded polished pebble with cream, green, orange-red, and brown orbicular patterns, opaque to slightly translucent, and vitreous to waxy luster. Quartz is cryptocrystalline, so individual crystals are not visible; cleavage is absent and fracture is conchoidal.

Identified August 16, 2026More mineral →

Explore Polished ocean jasper (orbicular jasper) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms from silica-rich volcanic or hydrothermal fluids filling cavities and replacing volcanic rock, producing concentric orbicules; many Madagascar examples formed in Paleogene volcanic settings roughly 25–35 million years ago.

Uses & applications

Used for cabochons, beads, carvings, polished palm stones, and collectible specimens; its value is mainly ornamental rather than industrial.

Geological facts

Orbicular jasper is often marketed as ocean jasper, though “ocean jasper” is a trade name rather than a single formally defined mineral species.

Field identification & locations

Identify it by its distinctive rounded concentric patterns, opaque jasper body, and glassy polish; major sources include Madagascar, Mexico, Australia, and the western United States. Acid will not visibly fizz, unlike calcite-rich lookalikes.