​Found at the bottom of a lake in N. Maine. Weighs about 2 lbs, apparently stone.

My son pulled this up from a pond in downeast maine. The longer end has a sharpened tip, like an axe. Seems like stone and isn’t magnetic as far as I can tell, if it is the corrosion gap is big enough to nullify. It’s probably something obvious and dumb, but I’m not imaginative enough to come up with it. Google image search didn’t give me much to go on.