sedimentary
Ocean Jasper
Orbicular Jasper (Silicon Dioxide, SiO2)
Hardness: 6.5-7 (Mohs). Color: Multicolored (white, brown, beige, green, pink). Luster: Vitreous to dull. Crystal Structure: Hexagonal (Trigonal, microcrystalline). Cleavage: None. Specific Gravity: 2.58-2.91.
- Hardness
- 6
- Color
- Multicolored (white, brown, beige, green, pink)
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6.5-7 (Mohs). Color: Multicolored (white, brown, beige, green, pink). Luster: Vitreous to dull. Crystal Structure: Hexagonal (Trigonal, microcrystalline). Cleavage: None. Specific Gravity: 2.58-2.91.
Formation & geological history
Formed as a silicified rhyolite or tuff where silica-rich fluids cooled and precipitated over millions of years, often in volcanic flow areas. The orbicular patterns are unique to specific formations in Madagascar.
Uses & applications
Primarily used for ornamental purposes such as spheres, carvings, jewelry (cabochons), and as a popular collector's mineral.
Geological facts
Ocean Jasper is only found on the coast of Madagascar and can sometimes only be mined during low tide. The distinct 'eyes' or circles are called spherulites.
Field identification & locations
Identify by its unique orbicular (circular) patterns and frequent presence of druzy quartz pockets. Found exclusively in the Marovato region of Madagascar.
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