I found this wood/hide/stone hammer in my grandmother’s collection of odds and ends. She said that she found it in the woods of Nothern Minnesota around 1950.
It is about 20" long, the stone is about 6" in diameter, and there is a groove in the stone where the wood wraps around.
The intact wooden handle makes the pieces suspect as to whether it is ancient or not. I have one about that size and shape, it dates from 500BC , wood would not have survived that long intact. More recent Native Americans would generally have used tools purchased by the White Man, espically one that takes alot of abuse. What you have looks like what is called a Maul hammer, a style that wasn’t used for about the last 1500 years.
But it could be an old piece that someone found and made a handle for early in the 20th century. There was a lot of interest in white men dressing up and playing “Indian” back in the day. http://www.redmen.org/
The stone may be real, and the handle a later replacement. We have several of those in the collection of the museum in which I work. Collectors would replace wooden handles for displaying their treasures, which would get sold or passed around intact before finally coming before the eye of our expert who would crankily yank off the offending modern additions.
Take it down to your local museum. Even if they don’t have an expert on site (which most don’t-- they usually have consultants come in when they need assistance in identifying artifacts) they’ll be able to steer you to one.
If you can’t find a recommended expert try locating some Native American artifact collectors clubs in the area which it was found. Even if you’re considering selling it, don’t mention it to the people you have look at it. Sad to say, but some people will say a valuable item is worthless in hopes of buying it cheaply.