Purchase a light or dark travertine filler kit from you local hardware or homebuilding store. Choose the shade based on the color of your tile.
Clean the cracked, scratched or nicked area with soap and water. Rinse it with clean water until no soap remains.
Dry the travertine tile thoroughly. Use a hairdryer and blow warm air on the tile for at least 15 minutes.
Mix the travertine filler powder and water in a cup. The consistency should mimic peanut butter when mixed properly.
Apply the filler mixture to the damaged area with the wooden spatula. After covering the area, press down firmly and release the air bubbles. Work the filler into the area until it becomes level with the surface.
Wipe the travertine tile with a damp sponge and remove any residue. Allow the filler to set for two hours. Repeat the process after this time has elapsed if the damage is still apparent.
Wait 24 hours for the mixture to cure. Use the damp sponge to remove any additional residue.