Home » Categories » Natural Stone Q & A’s

Granite with marks appearing

Hi Maurizio, We recently had a black granite worktop installed in our new kitchen. We have noticed that where ever we leave a cup down especially hot tea that a ring is appearing. It's almost as if the heat is fading the granite. I am aware that granite is supposed to be able to withstand heat upto 900F. I think we have be have been cheated on the standard of granite. How can we tell? The granite is only about 4 months old we cannot imagine what it will be like in 4 years time. I would appreciate any help or advice that you can share. Regards, Sinead Fitzpatrick
 

Dear Sinead:

Let's start by saying that the only black mercantile granite that has the legal right to be called “Black Absolute” is the one coming from South Africa. However, in real life, when one mentions “Black Absolute Granite” one's talking about a huge variety of stones coming a little bit from all over the planet, each and every one of them not a geological granite by a long shot, and each and every one of them with different characteristics. If that wasn't confusing enough, each and every one of them are processed with even if so slightly methods – which again can make a difference.

There used to be three possibilities to explain the problems that you are experiencing, which are here listed in order of probability (the first being the most probable):

  1. The fabricator applied an impregnator/sealer to it believing that it's granite. No impregnator/sealer will ever be absorbed by black granite; therefore it won't do the first thing about doing what's designed to do, which is prevent stains. (What you have are NOT stains, and no impregnator/sealer on the planet can prevent those.) Many a sealer turn out to be sensitive to acids; hence the “mysterious etching.” Not on the stone, rather on the sealer that had no business being there.
  2. The slab had been “doctored” by the factory by applying some sort of black shoe shine in order to make it “blacker” and, therefore more “sellable.” After a while the “shoe shine” will begin etching as it gets eaten away by acidic spills. The true color of the stone is dark gray.
  3. It is one of those as-rare-as-a-white-fly “mutt” stones with some traces of acid-sensitive minerals in it. In this case it is actually the stone that gets etched.

 

In the last couple of years there's been a change in the scenario above. Another possibility has entered the scene:

 

4.   Certain manufacturers apply some sort of protective wax to the slabs. It is not actual “doctoring,” since there's no alteration to the color of the stone, but    the result is the same as if the slab had been “doctored” with the “shoe-shine.”

Finally, case 3 above is not as rare as it used to be anymore. At least a couple of “Black Absolute Granites” allegedly from India and China entered the scene recently and are terrible “mutt” stones. Since they are cheap (to the importers) they push them like cra zy at full black absolute granite prices.

Having said all that, the remedy to the points 1, 2 and 4 is to remove whatever it is that's sitting on the stone surface, by either stripping it chemically by soaking it with Methylene Chloride, or mechanically, by rubbing on the stone surface a polishing compound for marble (NOT for granite!) with a little bit of water. However,, case 2 is big time consumer fraud.

Case 3 is terminal but it is also full-fledged consumer fraud.

 

All things considered, black granite – which should be considered among the most enjoyable materials as a kitchen countertop – has made it out my own list of recommended stones.

Until the industry will not straighten its act up by becoming serious about the classification of all the different “granites” on the marketplace and dictate strict rules and guidelines about their characteristics and implied guarantees to the consumers, my position is going to be that from now on.

You can help! Actually, as a consumer of stone you're the best qualified to make things happen! Will you now please read and sign our Statement of Purpose by logging on at: http://www.marblecleaning.org/purpose.htm? By spreading the word about this valuable site among your friend & family and the stone trades' people you've been dealing you will be rendering everybody a valuable service!

Thank you.

Ciao and good luck,

Mauri zio Bertoli

 

www.marblecleaning.org – The Only Consumers' Portal to the Stone Industry Establishment!

Attachments Attachments
There are no attachments for this article.
Comments Comments
There are no comments for this article. Be the first to post a comment.
Related Articles RSS Feed
Marble, Travertine, or Porcelain
Viewed 0 times since Wed, May 16, 2007
Grout Film on Travertine Tile
Viewed 0 times since Mon, Nov 12, 2007
water stain film over surface of granite
Viewed 0 times since Fri, Jul 10, 2009
grout line thinckness
Viewed 0 times since Wed, Jun 13, 2007
etching on table top
Viewed 0 times since Fri, Sep 28, 2007
Sealing limestone, marble, granite in shower
Viewed 0 times since Wed, Dec 19, 2007
Travertine (filled and polished) with epoxy grout
Viewed 0 times since Sat, Dec 18, 2010
Granite Sealing
Viewed 0 times since Wed, Aug 15, 2007
7 year old white marble shower walls
Viewed 0 times since Thu, Aug 23, 2007
Limestone
Viewed 0 times since Fri, Oct 10, 2008