Updated as of June 2026
Onyx vs Obsidian
| Onyx | Obsidian | |
|---|---|---|
| Price / carat | $3 to $40 | $1 to $40 |
| Hardness (Mohs) | 6.75 | 5.25 |
| Color | Black, White, Banded | Black, Brown, Gray, Rainbow sheen |
| Treatment | Dyeing (most black onyx) | Typically untreated |
The bottom line
Onyx and Obsidian both make beautiful jewelry. Choose by the look you want first, then weigh hardness against how hard you will wear the piece, and let price settle close calls. Read the full guides for Onyx and Obsidian.
Frequently asked questions
Is Onyx or Obsidian more durable?
Onyx is harder (Mohs 6.75 vs 5.25), so it resists scratches better.
Which is cheaper, Onyx or Obsidian?
Onyx runs about $3 to $40 per carat and Obsidian about $1 to $40 per carat, so Obsidian is usually the more affordable choice.
Which should I choose?
Pick Onyx if you want black tones and Obsidian if you prefer black. Match the stone hardness to how you will wear it and let budget break the tie.