Onyx: water, sunlight and care
Yes. Onyx is safe in water, so a brief rinse under running water is fine. Dry it with a soft cloth. Sunlight is not suggested for any stone in Heptyx.
Onyx at a glance
| What it is | Chalcedony |
|---|---|
| Hardness (Mohs) | 6.5–7 of 10 |
| Water | Safe in water. |
| Sunlight | No fading record in the sources. |
| Good to know | Most black onyx is agate coloured with a sugar process. |
How to care for Onyx
- Moonlight: In tradition, stones are left in moonlight overnight, especially around the full moon.
- Sound: In tradition, a bell or a singing bowl is rung near the stone.
- Running water: Rinse briefly under running water and dry with a soft cloth.
- Sunlight cleansing is not suggested for any stone: many fade, and a missing record does not mean a stone is sun-safe.
- Salt is not suggested: it can harm porous and soft stones.
Questions
Is Onyx safe in water?
Yes. Onyx is safe in water, so a brief rinse under running water is fine. Dry it with a soft cloth.
Can Onyx go in the sun?
Our sources have no fading record for Onyx, but Heptyx does not suggest sunlight for any stone: a missing record does not mean a stone is sun-safe.
How hard is Onyx?
Onyx is 6.5–7 on the Mohs scale of 10.
Sources
- geology.comAccessed 14 October 2026
- gemsociety.orgAccessed 14 October 2026
- gemsociety.orgAccessed 14 October 2026