sedimentary

Ocean Jasper

Spherulitic Chalcedony (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Variegated greens, pinks, whites, and browns with 'orbicular' patterns; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None

Hardness: 6
Luster: Vitreous to waxy

Identified March 28, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Variegated greens, pinks, whites, and browns with 'orbicular' patterns; Luster: Vitreous to waxy; Structure: Microcrystalline; Cleavage: None

Formation & geological history

Formed as a result of rhythmic precipitation of silica around a nucleus (orbicular growth) within volcanic rhyolite flows, likely during the Cenozoic era. Found in the intertidal zones of Madagascar.

Uses & applications

Primarily used in lapidary arts for polished spheres, cabochons for jewelry, and as a highly sought-after decorative specimen for mineral collectors.

Geological facts

Ocean Jasper is only found on the coast of Madagascar. The primary veins can only be reached and mined during low tide by boat, making it relatively rare compared to other types of chalcedony.

Field identification & locations

Identify by its unique orb-like 'eyes' or circular patterns and varied colors. Collectors should look for high contrast and distinct circular patterns without fractures. Found exclusively in the Ambolobozo peninsula of Madagascar.