sedimentary
Ocean Jasper (Orbicular Jasper)
Spherulitic Chalcedony (SiO2)
Hardness: 6.5-7 (Mohs scale); Color: Variegated greens, creams, and whites with circular patterns; Luster: Vitreous to waxy; Crystal Structure: Cryptocrystalline; Specific Gravity: 2.6-2.7
- Hardness
- 6
- Color
- Variegated greens, creams, and whites with circular patterns
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Variegated greens, creams, and whites with circular patterns; Luster: Vitreous to waxy; Crystal Structure: Cryptocrystalline; Specific Gravity: 2.6-2.7
Formation & geological history
Formed as a result of rhythmic precipitation of silica around a nucleus in volcanic environments, typically in shallow marine settings or through hydrothermal replacement of rhyolite. Primarily found in deposits dating to the Cenozoic or Mesozoic eras.
Uses & applications
Primarily used as a semi-precious gemstone for jewelry, lapidary work, cabochons, and as a popular specimen for crystal healing and mineral collecting.
Geological facts
Ocean Jasper was only found in one specific location in Madagascar and can only be mined during low tide. The original vein is considered largely exhausted, making high-quality specimens increasingly rare.
Field identification & locations
Identify by distinct 'orbicular' or eye-like circular patterns against a contrasting matrix. It is exclusively found along the coast of Northwest Madagascar. Collectors look for high contrast and clear orb definitions.
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