Tile picture framing.
We come across picture framing issues from time to time. If often occurs when natural stone tiles have been impregated before grouting and the impregnator stops the moisture from the grout coming back up through the tiles which in turn leaves a stain around the edge of the tile. The stain is often just under the surface rarely is it any deeper. The process is fairly straight forward but it does involve grinding and polishing, still better than having to rip the floor up !.