A wall made of stone can be a freestanding garden wall or a hillside retaining wall. This type of wall is always a beautiful addition to an outdoor space. A wall made of stone, in actuality, is almost always a concrete masonry unit wall that has been covered in stone in such a fashion that it appear to be built entirely of stone.  When stone is installed correctly it gives the impression that an entire wall is completely constructed of stone. There are many types of stone to choose for the veneer of a wall.  There are multiple ways of installing each type of stone in order to create a different pattern or design.