Before adding grout, clean the surface of the tile and remove any spacers used when setting the tiles.
Completely seal the stone tiles using a natural stone sealant applied following manufacturers’ instructions; this will prevent the stone from being discolored by the grout.
Apply the grout using a grouting float. Move the float in a circular motion, making sure that grout completely fills gaps between tiles. Important: Only grout as much tile as you can clean off on a few minutes. Don’t let the grout dry on the surface of the tile or cleanup will be much more difficult and the tile can actually be damaged.
When grout has dried to a light haze, wipe the tile surface clean with a damp sponge. Be careful not to wipe grout from between the tiles.