I was called to the fireplace problem which was installed about 5 years ago and was perfectly fine untill they start using it this year. The problem is that the stone is loosing color only in the top section, right above fire box which is affected by heat. When I touched back side of that slab, I have noticed oily substance (was oil used to enhance the color????). Customer used only water and soap to clean it over those years. I think it is honed slate but not sure. It is also very uniformed colored, unusual for the slate. Customer made a call to the builder but no avail info. I am puzzled and need your help with these questions:

What stone it is?

What is happening?

How to restore this stone?

Pictures are attached and I am going there tomorrow to do countertops.

Adam Bartos

BiO Tile