mineral
Green Onyx (Banded Calcite)
Banded Calcite / Aragonite (CaCO3)
Hardness: 3 on Mohs scale; Color: Light to lime green with white/tan banding; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Hexagonal; Cleavage: Perfect rhombohedral; Specific Gravity: 2.71
- Hardness
- 3 on Mohs scale
- Color
- Light to lime green with white/tan banding
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 3 on Mohs scale; Color: Light to lime green with white/tan banding; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Hexagonal; Cleavage: Perfect rhombohedral; Specific Gravity: 2.71
Formation & geological history
Formed by the precipitation of calcium carbonate from cold water springs or in caves. This specimen is post-Paleozoic and likely from recent geological epochs.
Uses & applications
Commonly used for ornamental carvings, polished points for crystal healing (metaphysical purposes), home decor items, and interior tiles.
Geological facts
While sold as 'Green Onyx', it is chemically calcite or aragonite, not true onyx (which is a form of chalcedony/silica). It is much softer than true onyx and can be scratched with a copper coin or steel blade.
Field identification & locations
Identify by its characteristic banding, softness (can be scratched by a knife), and strong reaction (fizzing) when exposed to a drop of white vinegar or dilute HCl. Found widely in Mexico, Pakistan, and Brazil.
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