sedimentary

Ocean Jasper

Orbicular Jasper (Silicon Dioxide, SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Green, cream, and brown mottled patterns; Luster: Vitreous to waxy after polishing; Crystal system: Trigonal/Microcrystalline; Cleavage: None; Fracture: Conchoidal.

Hardness: 6
Color: Green, cream, and brown mottled patterns
Luster: Vitreous to waxy after polishing

Identified July 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Ocean Jasper is a variety of chalcedony containing inclusions of iron oxides and silicified rhythmic orbicules. It formed as a product of secondary mineralization in rhyolitic flow rocks in Madagascar where silica-rich fluids cooled and crystallized over thousands of years.

Uses & applications

Primarily used for lapidary arts, jewelry making (cabochons), interior decoration, and as a popular specimen for crystal collectors.

Geological facts

The most famous source is found on the coast of Madagascar and can only be mined at low tide. This specific variety is prized for its 'orbicular' patterns and diverse color ranges.

Field identification & locations

Identify by its unique orb-like patterns and wide variety of colors within a single specimen. It is much harder than glass and can be found almost exclusively in the Marovato area of Madagascar.