There is no possible way that anyone could drill a hole in hard rock with an auger! You would use a star drill, or something similar. Drive the drill in with a sledgehammer, which crushes the rock directly under the edges of the drill, then give the drill a fraction of a turn to get new rock under the edges for the next blow. The edges of the star drill are straight, unlike the spiral that goes up the sides of an auger. An auger is more suited for materials that can be cut with a sharp edge, such as a bung cork, wood (boring auger), or dirt (post hole auger).