I agree with everyone that says it looks like a flint celt, chisel, or hoe in form. The thing that puzzles me is what appears to be the strange patination, or cortex remains. It looks as if this item was made out of a natural stone that was pretty much this shape to begin with, and minimal flaking was needed to get it to it's current shape. It looks as though bits of the cortex remain all over the piece. Either that, or it is an artifact that was re-worked anciently, with the greyish areas being the newer re-working, and the darker brownish areas being the older surface. Anybody else see the patina as strange?