The tool you use will depend on what sort of cut you are doing and how many marble tiles you plan on cutting. If you just have to cut a few tiles design, a glass cutter will suffice. If you need to cut more tile, however, a tiling tool or a wet saw might be more convenient.
Use a pencil and a square to measure and mark your floor tile. A square is a special ruler shaped like a right angle. Align the horizontal edge of the square with the bottom edge of the tile. Use the vertical edge of the square and a pencil to draw your guideline. This method is better suited to small jobs where you just need to cut a few small tile. It is not suitable for cutting corners or curves.
Set the tile down onto a sturdy surface and reposition the square. A workbench or plywood would work the best for this. Move the square off to the side so that it is right next to your marked line. This will allow you to cut right along the line without cutting into the square.
Score the tile with the glass cutter. Press down on the bathroom tile with the glass cutter, then drag it across the line that you drew, using the square as a guide. You may have to score the tile a few times in order to make a shallow cut. If you can’t find a glass cutter, try a carbide tipped pencil instead.
Snap the tile over a wire hanger. Place the polished tile on top of a wire hanger. Make sure that the hanger is aligned with the line that you scored. Next, press down on the un-scored edges of the tile until it snaps. if you scored from left-to-right, press down on the top and bottom edges, and vice versa. If you scored the tile close to the edge, snap off the thinner side with tile nippers.
Smooth the edges of the tile with a brick, if needed. You can do this by rubbing the cut edge of the marble tiles design back and forth across a brick or some concrete. This will buff away any roughness, much like sandpaper would on a block of wood.