How can I fix white wine etch damage on my onyx table?

Q. Someone spilled white wine on my onyx table last night. I wiped it up, but this morning I see that it looks like it penetrated the table and left a dull finish about 15 inches wide. Any suggestions on what to do? I have a feeling time is of the essence.

A. Unfortunately, it sounds like your onyx table has etch damage, which is a common issue with calcium-based stones like onyx and marble. 

Just so you know, etching isn’t the same as staining. It’s a chemical reaction. Even though you wiped the spill up right away, etching can happen within seconds—especially with highly acidic substances and soft, sensitive stones like onyx. It doesn’t need time to soak in like a stain; the damage begins as soon as the acidic substance touches the surface and reacts with the calcium content in the stone.

Etch damage often dulls the finish and leaves a cloudy or chalky discoloration. Its appearance can vary depending on factors such as the type of stone, the strength of the acidic substance, how long it remained on the surface, and other conditions.

To address your concern that time is of the essence, well, it's not. Not really. Since you wiped up the wine in a timely manner, no new damage is happening. Of course, if you do nothing, the discoloration will remain there until the situation is resolved. That might bother you, but the etch damage is not going to get worse the longer you wait. It is possible that dirt and contaminants can be a little harder to clean off of that area than the smoother surrounding stone. 

Your next step depends on one important detail: what type of finish does your onyx table have? Is it a polished surface with a glossy, mirror-like shine, or more of a satin or matte finish?

If your table has a polished finish, and the etch marks are relatively light, you may be able to improve the appearance using a high-quality marble etch remover or polishing powder. These products are formulated to gently buff out minor etching and restore some of the lost shine.

That said, keep in mind that DIY methods are best suited for shallow etch marks. If the etching is deep, covers a large area, or has impacted the natural clarity or color of the onyx, the product may not fully restore the surface to your satisfaction. Onyx is especially delicate, and its translucent nature can make damage more visually apparent—even after polishing.

If your onyx has a satin or matte finish, forget using polishing compounds. Why? Because polishing will make the treated area shinier than the rest of the surface, resulting in an uneven finish. While it might remove the etch damage, the overall appearance won’t be consistent.

Given that you’re seeing a dull area about 15 inches wide, there’s a good chance this may be beyond the scope of DIY repair. We recommend reaching out to a professional stone restoration contractor who is equipped with the specialized tools and expertise to re-hone or re-polish the surface properly. To find a vetted PRO in your area, visit www.surfacecarepros.com and click on Find a PRO.

For more care instructions for your onyx, download our free Stone and Tile Care Guide.

ABOUT THE AUTHOR Fred Hueston is the Chief Technical Director at SurfaceCarePROS.com and Director at StoneForensics.com. He is also the author of Stone and Tile Restoration: The Manual, a comprehensive online manual for stone and tile restoration contractors. [Learn more about Fred.]