Back to guide
Onyx
Onyx is valued for its black, white-banded appearance and distinctive natural character. Quality and value depend on color, clarity, cut, size, origin, treatment, and documentation.
- Mineral family
- Chalcedony
- Chemistry
- SiO2
- Mohs hardness
- 6.5-7
- Colors
- Black, white-banded
- Common origins
- Brazil, India, Uruguay
- Wearability
- Best in protected settings and requires careful wear.
Treatments and synthetics
Black onyx is commonly dyed.
Care guidance
Use only a soft damp cloth and avoid heat, chemicals, impact, ultrasonic, and steam cleaning.
Buyer checklist
Confirm classification, treatment, dimensions, weight, origin claims, return terms, and any laboratory report before purchase.