
sedimentary
Green Onyx (Agate)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 6.5-7 Mohs; Color: Pale green with white and dark green banding/mottling; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None
- Hardness
- 6
- Color
- Pale green with white and dark green banding/mottling
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 Mohs; Color: Pale green with white and dark green banding/mottling; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None
Formation & geological history
Formed as a cryptocrystalline variety of quartz, typically in the gas cavities (vesicles) of volcanic rocks or in cold-water spring deposits through the gradual deposition of silica.
Uses & applications
Commonly used for ornamental carvings (eggs, spheres), cabochons for jewelry, decorative household items, and lapidary art.
Geological facts
Despite being called 'Onyx' in the trade, most material of this type is actually a dyed or naturally translucent variety of Chalcedony/Agate. True onyx has parallel bands, whereas 'Green Onyx' specimens often show more cloud-like or random mottling.
Field identification & locations
Identify in the field by its waxy luster and hardness (it will scratch glass). Collectors look for uniform color or unique 'landscape' patterns within the stone. Commonly sourced from Brazil, India, and Madagascar.
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