🔎 UNIDENTIFIED Stone tool or celt?

[I say Potato. What say u?]

Found this at the bottom of the Potato River in Hubbard County, MN. I believe it is granite and it has a full groove. Archaic period hammer stone?

Thanks in advance for the help and opinions.

 

[DizzyDigger]

Very cool find. Now, as to whether it's an ancient hammer stone or not..that question I'll leave to the experts.

 

[ToddsPoint]

Definitely an artifact. It shows pecking over the entire surface. It might be finished, or might still be an unfinished preform. It’s not granite. It’s a fine grained igneous rock called diabase. Diabase was the go to rock for celts and axes in the upper Midwest. Nice save!