This.
Contact your local police department and ask if there’s any correlation between recent grisly unexplained murders/house fires and newly gravelled driveways. And don’t give it as a gift to anyone you care about. However, do see if you can palm it off on a sworn enemy.
Definitely cursed.
To be clear, in the magnet picture, that’s some other permanent magnet holding it, right? Does it stick on its own to plain steel? If it’s holding its own weight like that against ordinary steel, it’s almost certainly of modern origin.
Yes.
I love that it’s hanging in front of a picture of itself.
-D/a
Stay away from the Frogurt.
And what the hell is that thing holding it up in the second picture? A giant coloured locust with a magnet in its thorax?
Yes it is. ‘Magnetrax’ spawned when OP first touched the stone. Please just ignore him for now.
The Indians may have seen magnetism as spiritual. A medicine man may have carved the stone and used it in rituals. A rock that could move another rock (iron ore) would have been very powerful magic in a pre-industrial society.
Even today people are selling magnetic bracelets for pain.
That’s really cool! Please keep us posted, OP, about what (if anything) eventually happens to this piece!
Beside a coin, to show it’s size.
Good point. Isn’t this how The Exorcist started?
Oh crap. Well it was nice knowing you Quintas. I’d avoid eating any pea soup for a while.
Ninja’d!..and outbid. 
But seriously, those are wicked cool carvings.
Do not try to clean, apply toothbrush, or apply some sort of chemical to clean. Part of the surface already looks weathered. With luck, experts might still be able to date it and identify its place of origin.
And no, don’t use it as a paperweight or even let too many hands hold it.
If you are taking bids, I’m there.
Another one, on Flickr:
Is there some law that says all antiquities and archaeological artifacts automatically belong to the Federal Gov’t, or anything like that? If you take it to a museum to inquire about, will they confiscate it?
Given its clearly magnetic aspect, I wonder if it is not a cast iron ornamental piece from an andiron or boot scraper or similar object. It might be quite old, (although not older than European settlement), or it could be fewer than 100 years old, simply weathered from being mashed in with gravel.
As to snake, turtle, or amphibian, etc., while it may not be anatomically correct for a given genus, there is no evidence, (yet), that its maker had any knowledge of various anatomies.