Questions for the stone travertine and granite

    2 Questions for the Stone (http://g603.net) guru

1. I have a travertine tumbled backsplash that matches the Counter (http://GialloFiorito.com) top 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 (http://tanbrown.org) custom medallion in one of our buildings and (http://maplered.com) 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??