Dark Stains on Black Granite

I have black granite counter tops installed and when I leave a wine bottle or water glass on them overnight I get a dark ring stain. They do not wipe out. I had the company over and they have not been able to remove them. They now have used a poultice on them and they are out but I have a lighter (gey) area were the poultice was used. They sealed the tops with a HmK s34 impregnater. What is wrong, do they need to replace the tops? Thanks Don

 

Dear Don:

If your stains are darker I must assume that you black “granite” countertop is hone-finished – although you don't say it. (On the other hand, if it were polished, how could you possibly make a stain darker than black?!...)

If that's the cas e:

 

1. The poultice was the wrong thing to do, because they were surface stains, not deeply imbedded stains.
2. The regular impregnator they used was the wrong thing to apply, because A) you never apply any impregnator to black “granite” – no matter how it is finished – because the stone is just too dense to take any impregnator in; and, B) it could always create problems. Like in your cas e, for instance.

 

Once again assuming that your countertop is hone-finished (or else I wouldn't have any answer to your problem), the only option that you have is to get rid of the useless impregnator first, and then apply a good-quality stone color enhancer like MB-6 to your countertop.

Read the following piece of literature that I wrote several years ago and copied and pasted to this question board countless times already to understand what I mean:

 

There are indeed different opinions on black honed “granite” surfaces, but there is a unanimous consensus about the fact that it presents maintenance issues.

The problem with honed black granite is that it is not, well … black any more! Most black stones are but an optical illusion: they become black only when highly polished, or when wet. (See the back of your slab to see the real color of your stone!) As you take gloss off the stone surface (and honing does just that) you lose depth of color and the stone turns gray; but when you wet it ... here it is black again! As you spill oily liquids, or you simply touch the stone surface with your fingers (perspiration), you're going to have all sorts of dark surface stains that are a terrible eyesore. Please notice that I said, surface stains, not imbedded stains. In fact, you can clean those stains off (though with lots of labor), while if they were imbedded you would have to poultice them out. If you apply an impregnator/sealer to the stone you will not solve your problem one bit: in fact the sealer will only prevent liquids from being absorbed by the stone (which in the cas e of black honed granite is an unlikely event to begin with), not the staining of its surface.

Any solution?

Well, yes: you have to give up the gray!

If you apply a good-quality stone color enhancer to your countertop instead of an impregnating sealer (a good-quality stone color-enhancer like MB-6 is also an impregnator/sealer) it will turn it permanently black, while preserving the hone finish. In that way, the surface-staining problem would be minimi z ed.

Let's just hope that your fabricator, in their “infinite wisdom,” did not apply an impregnator/sealer to your stone: this would have to be stripped (not an easy feat!), or else the color/enhancer wouldn't stand a chance to work properly. And the best of way to strip it would be by re-honing the entire countertop with a good-quality honing powder (diamond pads could leave swirly marks).

And don't you forget that in order to upkeep your stone and the color enhancer, your best bet is to use good-quality specialty products for stone. 

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Thank you.

Ciao and good luck,

Mauri z io Bertoli

 

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