Piece of cake! Try this:
http://www.defusco.com/ager-liter-p-1438.htmlThis is a color enhancing sealer called Ager. Make sure your affected area is clean and dry, then take a toothpick and paint the scratch ( and ONLY the scratch) with the Ager. Wait 5 minutes and hand buff dry with a cloth. The scratch will still be there but it will not be visible (except of course to you).
If you were going to repair it you could use our granite & Chip repair kit, but that is much more of a process.
http://www.defusco.com/granite-and-marble-chip-repair-kit-marble-repair-kit-granite-p-2475.htmlI would try the Ager first.
Mark