sedimentary
Ocean Jasper
Orbicular Jasper (Silicon Dioxide, SiO2)
Hardness: 6.5-7.0 on Mohs scale; Color: Green, brown, cream with circular patterns; Luster: Vitreous to waxy; Structure: Microcrystalline (trigonal); Cleavage: None; Conchoidal fracture.
- Hardness
- 6
- Color
- Green, brown, cream with circular patterns
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7.0 on Mohs scale; Color: Green, brown, cream with circular patterns; Luster: Vitreous to waxy; Structure: Microcrystalline (trigonal); Cleavage: None; Conchoidal fracture.
Formation & geological history
Formed as a rhyolite or tuff through hydrothermal precipitation of silica. The orbicular patterns result from spherulites growing in volcanic ash or lava flow. They are associated with the Jurassic period, roughly 145-201 million years old.
Uses & applications
Primarily used in jewelry (cabochons), interior decoration, and as a popular specimen for crystal healing and mineral collectors.
Geological facts
Ocean Jasper is only found in one specific location in Madagascar and can only be mined during low tide. It was rediscovered in late 1999 after being 'lost' for nearly 45 years.
Field identification & locations
Identified by its unique 'orbicular' (eye-like) circular patterns and multicolored banding. Found exclusively along the coast of Marovato in northwestern Madagascar. Collectors should look for high color contrast and clear definition in the circular eyes.
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