It almost looks like someone hit it with a torch testing the metal Or acid test.I don't think it was jewelry cause that would be a odd spot for a loop to hang it on a chain. It would be over the E not the S so the coin would be Oriented Correctly.
Quote: Somehow, part of the rim was protected from the toning process.
That light spot above the s in states is rough and sticks out on the edge. It is why I thought it might be plated. The light part on the edge looks like a thin layer has been removed. Not particularly like it was protected.