Doctored Black Granite Countertop Etching

by MHA
(Chicago)

QUESTION:

I have a bathroom vanity with what was advertised as a black granite countertop. We have now realized that the stone top was doctored to make it appear blacker, as sometimes you get a black residue on the rag when cleaning it.

It has cloudy white spots from water on it now that I cannot seem to remove. The largest one appears to have etched the surface a bit. At one point my husband applied a couple of coats of granite sealer on the surface (we can't remember for certain if there were white spots before the sealer application) but new spots continue to form.

I know that doctored stone is hard to figure out, but I'd really like to (1) remove the white spots and (2) prevent white spots from forming again. Ideally, I'd like to keep it as black as possible or even have a way to re-doctor it periodically over time. But the white spots are really a problem!

ANSWER:

If the granite countertop has been doctored, then the dye used to doctor it is what is etching.

That's the main reason doctored granite is such an issue. Frankly if a doctored granite slab performed just like a typical granite countertop no one would care that much except for the frustration of paying more for a somewhat in-authentic product.

In order to eliminate the etching problem you'll have to remove whatever is on the surface that is etching upon contact with acidic foods and substances... like a dye.


By the way.... water is not causing the spots. Something acidic (some bath products) or something too alkaline (like nearly all common house cleaners) is doing the damage.

The typical way to fix a doctored countertop is to strip the dye off with a powerful solvent. Nasty job, but when done you'll have a true granite countertop that should not etch.

Of course it won't be black or as black anymore.

Although, there are stones coming out of India and China sold as various black granites that are actually some type of mixed-breed stone that contains calcite and etches without any doctoring.

Most often these are sold as Absolute Black, which is just the worst fraud since AB traditionally is one of the very best most bullet-proof stones you can buy. True black absolute comes only from South Africa though.

Applying a granite sealer won't do a thing for this issue. Granite sealers protect against staining only. Staining and etching are two completely different issues.

Nothing absorbs during etching. It's a chemical reaction that eats away or uses up the reactants. So, on stone it eats away the stone. If doctored the acids corrodes and destroys the dye exposing the lighter-colored actual granite surface beneath.

You'll find complete information about granite sealers and stripping any surface substance from granite countertops in the All About Sealing e-book.

Good Luck,
Ryan

P.S. Find the recommended best product brands for cleaning marble, sealing, cleaning granite countertops, quartz and all natural stone.