sedimentary
Ocean Jasper
Spherulitic Chalcedony (SiO2)
Hardness: 6.5-7 (Mohs); Color: Multi-colored (green, pink, white, brown); Luster: Vitreous to waxy; Structure: Microcrystalline with orbicular radial cooling patterns; Cleavage: None (conchoidal fracture)
- Hardness
- 6
- Color
- Multi-colored (green, pink, white, brown)
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Multi-colored (green, pink, white, brown); Luster: Vitreous to waxy; Structure: Microcrystalline with orbicular radial cooling patterns; Cleavage: None (conchoidal fracture)
Formation & geological history
Formed in the Cretaceous period through hydrothermal deposition of silica within flow rhyolite or volcanic tuffs, specifically within the intertidal zones of Madagascar.
Uses & applications
Primarily used for lapidary work, jewelry, ornamental carvings, and by collectors for its unique aesthetic patterns.
Geological facts
Ocean Jasper is only found in one place in the world: the coast of Madagascar. It was originally discovered in the 1920s but its location was lost for decades until rediscovered in 1999.
Field identification & locations
Identify by its characteristic orbicular or 'eye' circular patterns throughout the stone. It is typically found near the shoreline, and original deposits were only accessible by boat at low tide.
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