Fading issues with black granite

March 1, 2008
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Some black granite imported into the U.S. is doctored with dyes and oils to darken the surface.


I have received numerous calls lately concerning the fading of dark granite countertops. The most common complaints seem to be on Absolute Black, Black Galaxy, Zimbabwe Black and a few others. I have heard many fabricators try to blame the fading on the misuse of cleaning chemicals, acids, etc. While one should not use inappropriate chemicals on granite surfaces, this is often not the reason for the increase in black granite fading.

What would cause a dark granite to fade?

Actually, black granite should never fade. However, some black granite imported into the U.S. is doctored with dyes and oils to darken the surface. Dyes can include homemade blends such as charcoal and linseed oil. Pre-packaged color enhancers are also used to darken granite. The fading is nothing more than the dyes and oils being removed. Of course, the wrong chemical will take the dye out faster, but I have seen many of these dyes removed using simply water and a mild cleaner.

The best prevention against this situation is to work with a reputable stone supplier with a proven track record, but if you encounter a slab that you suspect has been doctored, you can perform the following test to find out if it has been altered:

• Take a clean white rag and apply some acetone to the surface of the granite. If any residue or black color is observed on the top, it has been dyed. If you get no dye from the acetone, then take some MEK(Methyl Ethyl Ketone) and apply it to a different part of the slab. If you get any color transfer, the stone is dyed. These chemicals can be purchased at most home improvement or paint supply stores.



Dyes can include homemade blends such as charcoal and linseed oil. Pre-packaged color enhancers are also used to darken granite.

Can dyed granite be repaired?

The reason that granite is dyed in the first place is that its natural color may not be desirable, and the material is not as successful in the marketplace. For this reason, some factories use methods to doctor these slabs -- pawning them off as rich, dark granites.

Unfortunately, there is no fix other than to dye the granite again.



Many types of granite are treated with resins, which can enhance the color while also reinforcing microfissures in the stone. This process is much more structured, however, and leading international companies are applying state-of-the-art resin products with advanced equipment that has been specially designed for this purpose.

What else can darken the color of a stone slab?

Many types of granite are treated with resins, which can enhance the color while also reinforcing microfissures in the stone. This process is much more structured, however, and leading international companies are applying state-of-the-art resin products with advanced equipment that has been specially designed for this purpose. Resin-treated granite is widely accepted in the world marketplace, although there are some issues that need to be considered when working with these materials. For the most part, however, most issues have well-established solutions. For further information on the resining process and issues, see “Resin Slabs: The Good, The Bad and The Ugly” in the April 2004 issue of Stone World, page 132, or search for it in the archives at www.stoneworld.com.

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