Faded Color Marble Medallion

QUESTION:

I laid a new marble medallion outside in our entryway. I sealed it with a Sealant/Enhancer.


The marble medallion has withstood the weather and rain well. UNTIL recently, it rained for 7 days and 7 nights, non-stop. I live in Los Angeles. Very unusual rain. Finally it stopped.

After the marble medallion dried from the rain, the color was faded and dull like it had been washed out.

The marble used in the medallion is polished marble and its color originally was a rich orange.

Now the color is pink and dull. I have scrubbed the marble medallion 4 times with a Tile Stone Cleaner with no results. What can I do?

P.S. the grout did not fade. PLEASE HELP.
Thank you for your time. Bill

ANSWER:

Bill, nice job with the picture, which always helps, however, this is an unusual and tough question.

My best assessment would be acid etching has damaged the polished marble finish resulting in the more subdued color.

Pollution is the cause of "acid rain". With all the smog in LA and seven days of rain, it may be that the rainwater was acidic enough to etch the marble.

Etching is a chemical corrosive reaction with the marble itself. Basically, the acid eats into the marble destroying the shiny polished layer and exposing the more raw marble underneath.

The marble polishing process causes the color to look more vibrant and saturated due to the change in light reflection.

If that mirror-like finish is eliminated, then you'll see the color of the marble as it exists naturally... more muted.


So, it isn't a matter of "cleaning marble" since the damage is likely to the marble itself. You need to repair the marble.

You can repair etching on polished marble using the Etch Remover / Marble Polishing products, which are designed just for this problem to restore the color and shine.

A sealer will not inhibit etching. Sealers help prevent staining, which is a completely different issue than etching.

Etching begins immediately upon contact with an acidic substance.

The longer the acid or caustic substance remains on the surface the more severe the damage from etching will be.

So even if the rain was only mildly acidic, constant contact for seven days could do it since the chemical corrosion continues as long as the acid is exposed to the surface.

A second possibility may be related to the sealer.

First a little FYI... Typically you would not seal any stone in a wet environment especially if it is on the ground. It's always best to do as little as possible to stone.

Applying a sealer to outdoor floor tile can sometimes create problems with water getting trapped in the stone.

Even though most sealers do allow the stone to breathe so water in the stone can evaporate it is important to understand that sealing is not mandatory or absolutely required to maintain the stone.

The main reason to apply a sealer is to help prevent stains from occurring on the exposed surface.

The risk of getting a stain on your outdoor medallion is minimal. And stains are easy to remove and rarely permanent anyway.

Sealers just make marble maintenance more convenient.

It may be that the sealer itself is etched or has undergone some other reaction to change the look of the stone.

You may try stripping the sealer with a solvent like methylene chloride. If the problem is with the sealer, stripping it off will reveal the marble as it was prior to sealing.

Also, a color-enhancing sealer is not designed to be applied to polished marble.

Color-enhancing sealers are designed to be used on honed and tumbled finishes to help saturate the color and provide a "wet look".

Polishing marble brings out the color as much as possible, so a color-enhancer is of little benefit on a polished surface.

A regular impregnating sealer like the sealers we recommend is what you want with a polished surface.

But again, really not recommended for outdoor installations.

I think it is much more likely that the problem is etching of the marble itself though, so I'd recommend using the Etch Remover suggested above or just leaving it as is since you could have this same issue over and over.