sedimentary
Orca Agate
Chalcedony (Microcrystalline Quartz, SiO2)
Hardness: 6.5-7 Mohs; Color: Black, grey, and white with swirling patterns; Luster: Vitreous to waxy; Structure: Cryptocrystalline; Specific Gravity: 2.60-2.65.
- Hardness
- 6
- Color
- Black, grey, and white with swirling patterns
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 Mohs; Color: Black, grey, and white with swirling patterns; Luster: Vitreous to waxy; Structure: Cryptocrystalline; Specific Gravity: 2.60-2.65.
Formation & geological history
Formed primarily in Madagascar within volcanic cavities or sedimentary layers. It is a form of cryptocrystalline quartz that precipitates from silica-rich groundwater over millions of years.
Uses & applications
Popular in the metaphysical community, used for decorative carvings, polished towers, and lapidary art.
Geological facts
Named after the Orca whale due to its distinctive black and white patterns that mimic the markings of the marine mammal. It is considered a relatively recent find in the gemstone market.
Field identification & locations
Identified by its characteristic opaque grey-to-black base with fluid white 'cloud' or 'spot' inclusions. Primarily found in Madagascar. Collectors should look for high contrast and minimal fractures.
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