Questions for the stone travertine and granite

    2 Questions for the stone guru

1. I have a travertine tumbled backsplash that matches the countertop much better when wet.  Will one of these enhancing sealers darken the tile so the color is similar to what it is when wet?  If so, should I seal before or after I install or both?
2. We have a large granite custom medallion in one of our buildings and a piece of absolute black fromt eh surface about the size of a quarter chipped off.  I could send a photo if easier for your.  Does anyone make a filler in black which will hide this imperfection??