I would like to say thanks to those who added some construct to there opinions on this stone. I probably posted these in haste as this stone is extremely difficult to represent in 2D. The gabbro is like predator camo which makes the stone's angles hard to define. There is also the striking contrast from the 90 degree handle to the head's curves which is hard to fully understand with holding it.
For those doubting this stone based on it's lack of a wood handle feature, like a number of stone tools there is some overlap on the use of terms, so please allow some variance with my subject title choice. It's easy to get conditioned to the type of tools found in a particular area or from a particular time. This is a bit of an odd duck. I am probably leaning towards something between a hand chopper and hand axe (shaping wood not felling trees)
As asked in one of the replies - What is it about this stone that makes me think it man made?
Fair question.
1. The fully 90 degree rectangle handle that quickly transfers into a curvy wedge is not natural. This was the only reason I did not put this stone down after uncovering it. It felt unnatural so I added to the backpack for a closer look later.
2. The bottom is flat and much smoother than other facets.
a. Not natural with respect to this stone's other features
b. Shows this stone could have been used as a hand axe\chopper\bone crusher and a grinder
3. There are a number of area's that have distinct pecking evidence. See Pics.
4. The front edge has two very distinct impact fractures. See Pics
5. It is the correct material for a tool of this area - Wisconsin
6. It size and shape are in-line for a hand held tool (4.5" Long | Head 3.5" Wide). Weight 570 Grams
7. And the strongest attribute that makes me believe this stone is man made, it fits well in your grip.
On to pics
Picking to shape left side handle - Red border (Viewed from bottom of the stone | Left when viewing from handle to head)
Picking to shape top side handle - Orange border (viewed from top of the stone)
Picking to shape right side handle - Red border
Picking on bottom head - Red border
Striking edge impact fractures - Red arrows
Bottom view in response to comment that the stone does not have the shape of an axe. I think Mindcraft owes me some royalties.
Bottom line, I think this is an old stone tool which has seen considerable use. Probably looked a bit different when it was first made. I would assume the front edge would have been further extended and with a decreased angle.
Thanks for all the replies.
Ken...