The Stonecutter is similar to the Crafting Table as you need it to craft. You can craft stone related blocks. It was put in PE in 0.6.0 because of how crowded it is in the Crafting Table menu. It will probably be removed with the discontinuation of the MATTIS (Minecraft Advanced Touch Technology Interface System). It has an appearance much similar to a Furnace but with a gear on the top and sawblades and hammers around the front and back sides.
4 Cobblestone blocks are required to make a stonecutter. When crafted, it allows you to create stone based items.