gemstone

Ocean Jasper (Orbicular Jasper)

Silicified Spherulitic Rhyolite / Chalcedony (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5 - 7 on the Mohs scale; Color: Multi-colored, featuring pastel greens, creams, browns, and pinks with prominent concentric orbicular 'eyes'; Luster: Vitreous to waxy; Crystal system: Microcrystalline (trigonal quartz / chalcedony); Cleavage: None (conchoidal fracture); Specific gravity: ~2.60 - 2.65.

Hardness: 6
Luster: Vitreous to waxy

Identified October 3, 2026More gemstone →

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Physical properties

Formation & geological history

Formed during late-stage hydrothermal silicification of volcanic rhyolitic tuffs and flows, where spherulites (spherical radial aggregate crystals of quartz and feldspar) crystallized within silica-rich magma or ash layers and were later permeated by silica-rich waters.

Uses & applications

Commonly carved into polished decorative items such as eggs, spheres, and palm stones, and cut into cabochons for rings, pendants, and ornamental gemstone collections.

Geological facts

True Ocean Jasper is famously mined primarily from a remote coastal deposit along the shores of northwestern Madagascar near the village of Marovato. Because the original veins were located in the intertidal zone, mining was historically only possible at low tide by boat.

Field identification & locations

Identified by its distinctive rounded, concentric spherical 'eye' structures (spherulites), floral patterns, and diverse color banding set in a fine-grained jasper or chalcedony matrix. Found mainly in Madagascar, with similar orbicular varieties found in Mexico and the United States.