Etching and Watermarks on Marble Surfaces

More marble is damaged by acidic chemical exposure than any other single source. Most of this damage is from accidental spills.  However, a good percentage is caused by the use of improper cleaning chemicals. 

I speak to literally hundreds of clients each year with chemically damaged marble.  Here’s the breakdown (in order of frequency) of the events that damaged their stone:

1. Accidental Spill of an Acidic Substance (orange juice, lemonade, wine, vinegar, etc.)
2. Use of Improper Cleaning Chemicals (including accidental exposure)
3. Contact with Cosmetic Products (facial cleaners for acne, citrus based soaps & shampoos, etc.)
4. Embedded Watermarks and Stains from Cups, Glasses, and Bottles
5. Personal Accidents Around Toilet Bases (oops, I missed…)
6. Physical Scratches and Stunning
7. Pet Accidents (urine & vomit) 
8. Embedded Oils Stains (food substances, cooking oil, butter, essential oils, etc.)

As you can see, the top 5 causes of damage are either etches or watermarks. Let's explore each in more detail:

Etching

Acidic spills (orange juice, lemon juice, grapefruit juice, wine, vinegar, Margarita mix, certain cosmetics, “tile cleaners”, “bathroom cleaners”, “tub & toilet cleaners”, etc.) are the single-largest cause of etching. They will etch marble surfaces immediately – whether they are impregnated (sealed) properly, or not. Etches appear on your marble as spots or areas that are much duller than the surrounding stone, and they do not improve with normal cleaning techniques.

Etches can be classified into three categories:

Minor: Results in loss of shine / reflectivity. No roughness can be felt on the etched area when a thumbnail is scraped across the surface from an undamaged area into the affected area.

Moderate: Results in loss of shine / reflectivity. Slight roughness can be felt on the etched area when a thumbnail is scraped across the surface from an undamaged area into the affected area, but there is no visible pitting or “cratering”.  If the etch has caused a crater, you will feel (and sometimes see) a drop-off when performing the thumbnail test.

Severe: Results in loss of shine / reflectivity. Significant roughness can be felt on the etched area when a thumbnail is scraped across the surface from an undamaged area into the affected area, and there is visible pitting and/or “cratering”. Severe etches over 1/16 of an inch deep will require an epoxy patch or replacement of the stone.

You must make every effort to ensure that acidic substances (like those listed above, and others like them) do not come into contact with your marble. If they do, remove them immediately from the surface by wiping them inward on themselves to avoid spreading them to uncontaminated areas.

The good news is that you can remove minor etches yourself without tools or special expertise, on all but black or green marbles, by using our Etch Remover ProKit.

To learn more about the Etch Remover ProKit, click the following link or copy and paste it into your web browser:

https://www.mystonecare.com/Etch-Remover-Kit-p/mscprokit-etch.htm

As I stated earlier, there is no acceptable method to completely stop acid etching on marble surfaces.  There are topical, film forming sealers available that will stop acid etching, but they cause more problems than they solve.  This class of products is not recommended, nor do we sell or use them in this application for the following reasons:

• Nearly all have problems adhering to polished surfaces – they chip, flake, and peel.
• They are easily scratched - more easily than the stone, itself.
• They require more routine maintenance than the stone itself would.
• They must be stripped and re-applied on a routine basis.
• They look terrible – even when new they give marble a “fake” look

However, it is possible to both slow down the etching process and lessen the severity of acid etching through the use of engineered wax.  Engineered wax creates an invisible, ultra high gloss barrier between the acidic substance and the stone, thereby giving you valuable seconds (in some instances) to remove the substance from the surface before it reaches the stone.  Even if you don’t get to it in time to stop the etching, the damage will be less severe than it would have been on an unwaxed surface.  The down side?  ENGINEERED WAX CANNOT BE USED ON FLOORS. PERIOD. EVER.  Surfaces treated with engineered wax become EXTREMELY SLIPPERY, so it may only be used on tables, vanities, counters, Pullmans, or other surfaces that do not come into contact with foot traffic.

We have an outstanding Engineered Wax product available, and it is the same one used by hotels and casinos worldwide to protect and beautify the marble in their high-end rooms.  It is fast, easy to use, develops an ultra high gloss, and enhances the color of the stone, all while providing a barrier that significantly slows the etching process.

To learn more about Engineered Wax, click the following link or copy and paste it into your web browser:

https://www.mystonecare.com/engineered-marble-granite-wax-p/msc-waxl.htm

Oh, by the way, did I happen to mention it’s NOT FOR USE ON FLOORS?

To keep your Engineered Wax finish at its high gloss peak between applications, we recommend the use of Stone Pro Finishing Touch Ultra.  Finishing Touch Ultra is outstanding for “vanity” polishing on all natural stones, and works especially well in conjunction with engineered wax surfaces.  It is silicone based (rather than petroleum based), and will not remove engineered wax coatings with routine use.  It is also highly effective on granite and stainless steel.

NOTE TO EXISTING CUSTOMERS: Some of you may use our GranQuartz 113M 3-in-1 spray polish on your polished marble and granite surfaces.  Please be advised that 113M is petroleum based and will degrade surfaces treated with Engineered Wax.

To learn more about Stone Pro Finishing Touch, click the following link or copy and paste it into your web browser:

https://www.mystonecare.com/Stone-Pro-Finishing-Touch-Ultra-p/spftu.htm

Non-Acidic Water-Based Stains

Again, unimpregnated (unsealed) marble can stain if it comes into contact with colored, water (or other)-based substances. Tea, coffee, soft drinks, sauces, juices, wine, and just about any other colored substance you can think of can create staining that cannot be removed by routine cleaning techniques. In fact, just plain water (depending on the mineral and chemical content) can cause staining or color leaching on unimpregnated (unsealed) marble surfaces.  Worse yet, if the substance is acidic, you can get an etch and a stain at the same time!

To avoid these types of stains, please keep your marble surfaces properly impregnated (sealed)! There is no reason not to do it.  With one notable exception, “watermarks”, (that we will discuss in the following Section), proper impregnation will stop staining.  

If you should get an organic stain on your marble, in most instances Stone Pro Wet Poultice will remove it completely from marble surfaces. For heavier oil stains, Lithofin Oil Ex should be used.

Watermarks

Watermarks are the trickiest problem of all to deal with on polished marble.  They manifest themselves as discolored areas that conform to the shape of the cup, glass, bottle, or other wet object that was placed on the stone, then allowed to reside there until the fluid fully penetrated the surface.

Please note that watermarks can occur even on properly impregnated and engineered waxed surfaces!  How could this happen, you ask?  Because the discoloration is formed under the pressure of the object residing on top of the stone, driving the fluid in.  Impregnators and waxes are designed to function at atmospheric pressure, only.  They are not designed to stop fluids that are under (hydrostatic) pressure.  They will lengthen the time it takes for the watermark occur, they will lessen the severity of the watermark – but they will not stop it if the object remains on top of the stone, forcing the fluid in under pressure.  However, they still remain your single best defense, and can make the difference between a watermark that can be removed - or one that becomes a permanent eyesore on your stone. 

Watermarks can be stains (depending on the fluid under pressure), or they may be chemically induced loss of color (leaching).  And, yes – even plain water (depending on the chemical and mineral composition) can cause both leaching and/or staining on marble surfaces.

The best offense against watermarks is a good defense!  Here are some sound tips for avoiding them.  An ounce of prevention is worth a pound of cure…

• Always use coasters when placing cups, glasses, or bottles on marble surfaces.
• Keep a soft cloth handy on bath and bar counters to place wet containers on.
• Do not allow wet objects to reside on marble surfaces.
• Keep your non-flooring marble surfaces properly impregnated (sealed) and waxed.
• Keep your marble flooring properly impregnated (sealed).

Watermarks, just like etches, are classified into three primary categories:

Minor: Minor visibility on surface. Fluid has not fully penetrated the surface of the stone. Can be removed on all but black or green marbles with our Etch Remover ProKit.

Moderate: Readily visible on the surface. Fluid has penetrated less than 1/32” into the surface. Actual stains may be removed by using Stone Pro Wet Poultice. If color leaching causes the mark, the surface will require honing to remove the damaged area, then repolishing.

Severe: Very high visibility on the surface. Fluid has penetrated more than 1/32” into the surface. Actual stains may be removed by using multiple applications of Stone Pro Wet Poultice. If color leaching causes the mark, the mark must be considered permanent.