Maintaining Antiqued or Leathered Absolute Black Granite

by Kristen
(Boulder, CO)

QUESTION:

We recently had antiqued absolute black granite installed. The installer applied a granite sealer, but did not color enhance it as I like the lighter grey color.


I asked him about some streaks before he left, and he said they would wipe off over time. They didn't, so they came back, applied acetone, and then re-sealed it.

Then a week later I cleaned my glass stove-top with a cleaner made for pots and pans, some got on the granite surrounding the glass stove-top and has now lightened to a pale grey color.

I called the granite dealer and he said we should only use soap and water to clean, I explained that some of the stove top cleaner got on to the granite.

So my question is 1)is this normal, that you can only use soap and water on the stove top and if any of the stove top cleaner gets on to the granite that it would "stain" and...

2)what is he doing wrong? He said he will come back again, apply acetone and re-seal.

ANSWER:

Most likely it is the sealer itself that reacted to the cleaner and caused what is called an "etch mark."

Some sealers are reactive to acids and especially if there is dried sealer right on the surface, which is what the streaks were.

Etching is a problem with marble, because marble is reactive to acids, but granite is not sensitive to acids, so it is not the stone itself.

Absolute Black granite typically does not need sealing since it is so dense and essentially does not stain.

However, antiqued, honed or otherwise non-polished finishes can require additional granite counter top maintenance. They may take a sealer since these finishes leave the stone more porous than a polished surface.

The installer is not doing anything "wrong" per say... except perhaps not being exacting enough in his application of the granite sealer and/or testing to see if the surface even needed it.

Just to be clear... what you have is not a "stain." Stains occur when substances absorb into the stone turning the stone darker in color. You are not likely to ever stain this granite especially if it is sealed properly.


Your spot is a "lighter pale-grey color," so you need to find out what is being etched.

I suggest that you do a little maintenance and experimenting yourself.

Clean the etch mark area with acetone or even better use methylene chloride (sometime acetone isn't potent enough to remove a sealer). Use a soft scrub brush and clean an area about 1 foot square.

If the etch mark disappears, which I suspect it will, then you know that it was something (probably the sealer) on the surface that was etching.

If the spot is not removed, then either you didn't get all the sealer off or the stone is unusually reactive to acids.

Once cleaned an dried, perform the lemon juice test on the cleaned area. Let it sit for a few minutes and wipe clean.

Does it leave a lighter spot? It shouldn't. Now do the same on an area that was sealed, but not cleaned with acetone/methylene chloride.

Does the lemon juice leave a spot on this area?

If yes, then you have your answer... the sealer is reactive to acids and it is probably not being absorbed or applied properly.

It is very important, especially with low-absorbency stones like absolute black that you do NOT let any sealer dry on the surface.

You should also test for sealing granite countertops to see if a sealer is even needed once you have stripped the sealer off.

Try this and use the comment link below to report back your results and/or ask any other granite counter top maintenance questions along the way.

Regarding soap... It is often recommended, because everyone has soap, it's cheap and won't "hurt" your stone, but it is not recommended as soap residue builds up over time making the surface look dull and dirty... then you need to strip it off.

Just not a smart or effective cleaning method.

We recommend using products formulated specifically for natural stone. You'll find products and brands that we've found perform the best at the Stone Care Center.

For regular granite counter top maintenance and cleaning, you should use Granite Countertop & Marble Cleaning spray.

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