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.