sealing and stablizing top layer of sandstone

I have 18inch by 24inch cut slabs of stone for a an exterior wall cap - I think they are a dense sandstone 5 inches thick- the top layer has a beautiful multiclored "crust" which will flake off eventually leaving the gray solid layer below. I would like to harden and seal the top layer to protect it from from all flaking off over time. Is there a way to do this? Products that will penetrate and stabilize? Thanks, Robert

 

Dear Robert:

I'm afraid that you're gonna have to ask for help to a Higher Authority. To the best of my knowledge there's nothing available to us common mortals to accomplish what you're after.

Ciao and good luck,

Maurizio Bertoli