Rock Identifier
Ocean Jasper (Spherulitic Chalcedony (SiO2)) — mineral
mineral

Ocean Jasper

Spherulitic Chalcedony (SiO2)

Hardness: 6.5-7 (Mohs), Color: Multicolored with green, cream, and red orbicular patterns, Luster: Vitreous to waxy, Crystal Structure: Trigonal (microcrystalline/cryptocrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7

Hardness
6
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Physical properties

Hardness: 6.5-7 (Mohs), Color: Multicolored with green, cream, and red orbicular patterns, Luster: Vitreous to waxy, Crystal Structure: Trigonal (microcrystalline/cryptocrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7

Formation & geological history

Formed from hydrothermal deposits and volcanic activity where silica-rich fluids cooled slowly, creating orbicular (circular) patterns within a rhyolitic or chalcedony matrix. Specifically associated with the Marovato coast of Madagascar.

Uses & applications

Primarily used for lapidary work, jewelry (cabochons), ornamental carvings, and as a popular specimen for crystal collectors and mineral enthusiasts.

Geological facts

Ocean Jasper is only found on the coast of Madagascar and the original deposits could only be reached by boat at low tide. This specific stone is often called 'orbicular jasper' due to its eye-like patterns.

Field identification & locations

Identify by the presence of multicolored circular orbs or 'eyes' embedded in a dense matrix. It is extremely rare to find in the wild outside of Madagascar. Collectors look for high color contrast and spherical definition.