Since we are only able to see a small portion of the entrance the only suggestion I have is to paint the wall. The creepers might be a nice addition but I think paint would really make the wall and your plaques stand out.

Take a sample home and put lemon juice on it. What you will find is that the etches on dark marble show up white. Not at all attractive. And that's why only the white marbles are truly popular for kitchen counters. They show etches much less than the dark ones. Possibly use it as a vertical accent somewhere in your home (NOT a shower), but I wouldn't use it on any horizontal surface. Maybe a gorgeous full height backsplash where you have no uppers on a wall....or in an entry way directly facing you as a focal point. Think of it as art, not a work surface.

Ka_kamakshy interior architect , Did you check with your contractor why he thinks it will fall down. May be he hasn't done it earlier or he doesnt want to do it. It is very much feasible to clad the walls with marble/granite/ other finishes.

Please post the image of the kitchen...