It almost looks too course to be a sharpening stone wheel, possibly a weight used in an early manufacturing plant setting.
A bit of background information on where you found it would be helpful.
found it in the Ottawa river. in 2 feet of water. the stone is ribbed with iron i be-leave. the copper piece was found near by, passably fits in the center. or is not part of it at all
it's man made for sure , blow the pic up and see the reinforcing wire that gave the signal to his metal detector .
had to look up quern stone , never heard of one .
it's man made for sure , blow the pic up and see the reinforcing wire that gave the signal to his metal detector .
had to look up quern stone , never heard of one .