Nice looking work boot heel plate or 'heel shoe'.
These date to the mid-1800s, I've found a few of them in the farm fields.
The toe-taps that attached to the front of the boot are more common finds, as they were made of brass.
I go with heel plate. I remember that in grade school, SOME of us would have those on the heel of our "Beatle boot" shoes. THEY liked the sound of them walking around, the teachers?, not so much.