Also called a stone maul or stone splitter.  It is used for splitting large slabs of stone.  Use of the Slab Splitter is a two-person operation. One person holds the Slab Splitter angled on its edge, set in place along the line where the stone is to be split. The other person then hits it with the striking hammer.  With use, the breaking edge of the Slab Splitter will wear down.  This tool is not meant to be swung or used as a hammer.

Stone splitter used on Colorado Red Sandstone. Repeated swings with the sledge hammer against the splitter as it moves along a line will split the boulder into two pieces.These sandstone boulders are used for signs and memorial use by Kling Memorials/Butler Monument Company, Butler, Mo whose employees split them to size.

With the advent of the guillotine, hand splitting was done usually done only at the quarry to cut slabs down to a manageable size. Today it is used rarely in the memorial/granite business.  It is still used by stone masons to break up landscape rock.

Source: Interview with Melissa Phillips, Butler, Missouri.