
sedimentary
Orbicular Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
AI-generated identification · may be incorrectHardness: 6.5-7 (Mohs scale); Color: green, red, brown, tan; Luster: Vitreous to waxy (when polished); Structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91
- Hardness
- 6
- Color
- green, red, brown, tan
- Luster
- Vitreous to waxy (when polished)
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: green, red, brown, tan; Luster: Vitreous to waxy (when polished); Structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91
Formation & geological history
Formed from the deposition of silica-rich fluids in volcanic rock cavities or sedimentary layers. The circular 'orb' patterns result from radial growth of needle-like crystals around a central nucleus during the cooling or precipitation process.
Uses & applications
Primarily used for lapidary work, jewelry (cabochons), interior decoration, and as a collector's specimen.
Geological facts
Also known as 'Ocean Jasper' in certain Madagascar varieties or 'Poppy Jasper' when the colors are predominantly red. The circular patterns are scientifically known as spherulites.
Field identification & locations
Identify in the field by its distinct circular bands of color and extreme hardness (will scratch glass). Common in areas with ancient volcanic activity such as Madagascar, South Africa, or the Western US.
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