I purchased Terra Nuova marble tile from Floor and Decor for my kitchen backsplash (I know I have to be careful about staining and etching, but it's worth it to me because it's so beautiful). It had some holes in it (similar to what I've seen with travertine), so I spent most of today filling the holes in half of the tileswith Bostik NeverSeal Pre-Mixed grout. To my consternation, now that I look at the tile in the light, I'm finding that it seems to be shiny wherever the grout was rubbed during the filling process. I tried sealing one of the stones to see if the shine went away or was disguised, but it looked the same after sealing. I don't want to make the stone shiny, and I don't want to use stone enhancer. Do you think that the problem is that the grout is pre-mixed never-seal, and that an unmixed grout would work better? Or is there a different grout or other filler that you recommend for this purpose?

Thanks!