Before you try anything: always speak to a professional before cleaning, treating or applying any product to your stone. Every slab is different, and the wrong product can cause permanent damage. Contact us or a qualified stone restorer first.
Quick answer
Etch marks on onyx are surface damage from acid, so cleaning will never remove them. Onyx is fragile and easy to over-polish, so etches should be re-polished by a restorer who works with it. Once repaired, a protection film stops acids reaching the stone again.
First, check what you are dealing with
- Dull, pale or cloudy mark, often in the shape of a glass, drip or lemon wedge: an etch.
- Darker patch with no change in shine: a stain instead. See the stain guides.
- Slight roughness you can feel: a deeper etch that needs honing.
What you need
- A stone restorer
- pH-neutral cleaner for aftercare
Step by step
Confirm it is an etch
Look at the mark at a low angle to the light. Etches change the texture or sheen; stains change the colour.
Stop using acidic products
Switch to a pH-neutral cleaner so the etching does not spread while you wait for repair.
Book a restorer
Onyx needs a restorer who works with it regularly: it is softer and more fragile than marble and easy to over-polish.
Protect the result
Have protection film applied once the surface is even again, so the next spill cannot etch it.
What not to use on onyx
- Sandpaper or abrasive pads from the hardware store.
- Polishing powder on honed onyx, which leaves a shiny patch.
- More acidic cleaners in the hope of "evening it out".
When to call a professional
Call a restorer for etches you can feel, etching across large areas, bookmatched or feature slabs, and anything on onyx. Onyx needs a restorer who works with it regularly: it is softer and more fragile than marble and easy to over-polish.
Understanding etch marks on onyx
Onyx is calcite and usually highly polished, so a drop of lime or wine leaves a dull etch that catches the light immediately.
On polished, often backlit onyx, etches and scratches are visible from far away and light shines through any change in the surface.
Onyx needs a restorer who works with it regularly: it is softer and more fragile than marble and easy to over-polish.
Good to know
Etches on polished onyx are obvious, especially when backlit. Onyx is soft enough that DIY polishing can easily leave waves or hazy patches.
Stop it happening again
Whether yours is honey, white, green and pink banded onyx, often backlit, repairing it fixes today's mark; protecting it stops the next one. Our clear Stone Protection Film sits over the surface, so acids cannot etch it and liquids cannot soak in. Onyx is usually polished, so Gloss film is the natural match and keeps its reflective depth. It is installed across Sydney with a 10-year written warranty.
How we protect onyx · Fixing etch marks · Etch marks on every surface