igneous
Ocean Jasper (Orbicular Jasper)
Spherulitic Chalcedony (SiO2)
Hardness: 6.5-7 (Mohs scale); Color: Variegated greens, creams, pinks, and browns; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; SG: 2.6-2.7
- Hardness
- 6
- Color
- Variegated greens, creams, pinks, and browns
- Luster
- Vitreous to waxy
Identified More igneous →
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Variegated greens, creams, pinks, and browns; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; SG: 2.6-2.7
Formation & geological history
Formed through the rhyolitic volcanic process where silica-rich fluids cooled and crystallized into orbicular structures (spherulites). This specific variety is found in Cretaceous-age volcanic deposits.
Uses & applications
Primarily used for lapidary work, jewelry making, ornamental carvings, and as a highly sought-after metaphysical and collector specimen.
Geological facts
Ocean Jasper is technically a variety of chalcedony rather than a true jasper. It is called 'Ocean' Jasper because it was originally discovered and mined on the coast of Madagascar, accessible only at low tide by boat.
Field identification & locations
Identify by the presence of 'orbs' or circular patterns and its high polish. It is exclusively found in the Marovato region of northwestern Madagascar. Collectors should look for high contrast and unique 'flower' patterns.
