Cut Mosaic Tile
Mosaic tile comes in sheets. Individual tessarae (the little individual tiles) are adhered to a strong fiber backing.
Because you’re dealing with such small tiles, you really aren’t cutting the tile itself: you’re cutting between the tile. That’s the great thing about mosaic. So, let’s review your options for cutting mosaic tile, all of the super-simple:
1. Cut Between Tiles in Mosaic Sheet
This is always the first thing you should try. Nine times out of ten, you can slice through the fiber backing and get a perfect (or perfect-enough) fit.
How to do this is to turn the mosaic tile sheet upside-down, and cut through the backing with a utility knife.
2. Cut Individual Mosaic Tiles with Nipper
If you just have a couple of individual tiles within the mosaic sheet to cut, then snap them apart with a tile nipper (or nibbler).
If you have to cut a sheet of mosaic diagonally, your only option is to use the snap cutter. Cutting the tiles apart (#1) will not work.
3. Cut a Row of Mosaic Tiles with a Snap Cuttter
Cut a line of mosaic tile by setting the sheet in your snap cutter. The tiles will wiggle around a bit and protest, but with a steady hand you can position them and snap them apart.