According to MagicGrip , different substrates require different sealers. On most porous substrates water based penetrating surface sealers are generally used to go deep into the surface. On denser substrates solvent based surface sealers are generally used for a long-lasting result.
Application of surface sealers will result in very little change to the overall appearance of the tile and or stone, but it will repel water, dirt, mould etc. Tile and stone sealers will also leave a cleaner richer looking finish.
The best substrates for surface sealers include sandstone, brick, granite, and pavers. Before sealing a surface, the area should be chemically cleaned and high pressure cleaned, allowing it to thoroughly dry, and then the appropriate sealer applied.