I was reading an article today by Fred Hueston, founder of The National Training Center for Stone and Masonry Trades. The article is about the increasing number of complaints in the industry of fading black granite. He also outlines in the article a test for dye use. Here are some excerpts from the article.
The most common complaints seem to be on Absolute Black, Black Galaxy, Zimbabwe Black, and a few others. Real granite should not fade. Black granite imported from Asia and India is sometimes doctored with dyes and oils to darken the surface. Dyes can include homemade blends such as charcoal and linseed oil. The fading is nothing more than the dyes and oils being removed. The wrong checmical will take the dye out faster but many of these dyes can be removed using simply water and a mild cleaner.
Before purchasing granite or marble perform the following test to find out if it has been doctored. Take a clean white cloth and apply some acetone to the surface of the stone. If any residue or black color is observed on the top, do not accept it, 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 stone. If you get any color transfer, the stone is dyed. These chemicals can be purchased at most home improvement or paint supply stores.
There is no fix for faded granite - other than to dye the granite again.
I hope none of you need to use the test, but at least you have the info if you do.
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