If the problem is that the stone is breaking up, there are resins which help to consolidate stone. If the problem is that of oxidation, then the oxide needs to be removed first and then the surface protected with specific resins to make them impermeable. Where is the stone installed? In case it is a wall perhaps a water-resistant liquid may be needed every 5 years. Or perhaps an anti-graffiti. In restoration work, stone can be improved, it can be protected against external agents. The chemicals help to enhance the natural beauty of the stone.