The dark areas could be carbon spots. They are inside of the planchet. They do not go away. They get worse with time.


Note the pretty toning? It is from the carbon spot on the rim at 10:00 of the coin:


So they are not a good thing.


Note the pretty toning? It is from the carbon spot on the rim at 10:00 of the coin:


So they are not a good thing.





















