If your marble tile did not have a heavy object dropped on it or was not exposed to unusual circumstances, you will want to try and find a reason for any cracking or deterioration. Early trouble shooting at the first appearance of damaged tiles can save you much time and money in the future. If you notice cracking tiles, examine the surrounding grout and make sure that it is fully intact. Loose grouting will cause lose tiles and places your marble in danger of breaking or being chipped. If you have a crack in your marble tile flooring you may need to inspect the condition of your subflooring. An unstable ground layer of flooring will adversely affect your surface flooring. It is natural for a subfloor to become worn over time, but it will often wear in isolated areas. If this is the case, you can typically get away with resurfacing only the damaged area of your subflooring, and then replace the repaired tile on the surface.
You may be able to repair your broken or cracked tile to look like new. If an entire tile becomes lose and cracked, you will want to remove it from its installation for repair. You will need a flat, smooth surface to work on. Try to piece the tile back together to resemble the original tile as much as possible. You will want to clean the tile thoroughly before attempting to adhere any of the pieces back together. Acetone is a very effective cleaner for removing all dirt and grime from tile. Once you have cleaned the tile with acetone or a similar chemical, you can use epoxy adhesive or specialized marble repair cement to glue the tile together. If you are using marble cement, it is most effective when purchased from the manufacturer of the tile. Use a small paintbrush to cover the edge surfaces with adhesive. Press the pieces together and wipe away any excess adhesive. Allow the tile to dry before laying it back in place.
To replace broken corners, assemble a small wooden mold to fit around the corner of the tile. A broken corner on your tile countertop requires a specialized paste. Mix together polyester resin cement and marble dust to form a paste, pour it into the mold, smooth it over and allow it to dry for 24 hours.