do you have another tile? Im guessing you dont have grout though. If you have the spare tile, cut out the grout surrounding it first. This keeps other tiles from breaking when you take the broken one out. Hit the broken tile with a hammer lightly to get it to crack around. Use a chisel and hammer to pop it up and chisel away all the thinset under it too. Save a piece of the grout that came out and go to a store to match as close as you can. Put in your new tile with thinset, dry, and grout.