The stone splitting wedge is meant for splitting large stones that'd be too tough to move whole. It's the traditional way and still the best and quickest to split big rocks from the back.

Drill a series of holes into the stone with a suitable stone drill and insert the wedges into the holes. Then hammer the wedges with a mallet, and the stone will split along the line of the wedges. The bigger the stone, the more wedges you'll need.