The Stone Wall is a much improved version of the wall. It is currently the toughest form of wall that you can make and provides a barrier where one is needed. Unlike other forms of walls, the Stone Wall is not flamable. When building a wall, be careful to not form a perfect wall and leave yourself without access to a Hammer lest you be completely cut off from the rest of the world.
The Stone Wall starts off with 200 Health and when fully upgraded will have 400 Health. Stone is actually a very efficient wall building material. While it requires 2 Cut Stone to craft, you'll receive six pieces of wall. Since Cut Stone requires 3 pieces of stone, crafting the walls requires six stone total. This comes out to six pieces of stone for six pieces of wall or ultimately 1 stone per wall.