sedimentary
Ocean Jasper
Orbicular Jasper/Microcrystalline Quartz (SiO2)
Hardness: 6.5-7 (Mohs); Color: Multicolored (green, brown, pink, white); Luster: Vitreous to dull; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; SG: 2.6-2.9
- Hardness
- 6
- Color
- Multicolored (green, brown, pink, white)
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Multicolored (green, brown, pink, white); Luster: Vitreous to dull; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; SG: 2.6-2.9
Formation & geological history
Formed through the slow precipitation of silica around a nucleus in volcanic rhyolite flows. The specific variety shown is only found in the Marovato region of Madagascar.
Uses & applications
Primarily used for lapidary work, jewelry making, ornamental carvings, and by mineral collectors for its unique orbicular patterns.
Geological facts
The name is a trade term for a specific orbicular jasper from Madagascar. It was lost to the world for decades before being rediscovered at low tide on the coast in 1999.
Field identification & locations
Identify by its characteristic 'orbicular' or circular 'eye' patterns and its high polish. In the field, look for nodules within weathered rhyolite matrix, specifically in coastal Madagascar.
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