Hello everyone, can someone tell me if this is an ERROR COIN. The OBVERSE is totally different from the reverse of the coin. If this is an ERROR COIN. What kind of error is this. Thanks in advance
Narural toning can occur depending on how a coin is stored or kept.. Copper or Copper plated zinc such as yours will darken if only one side is exposed a certain way. Toning is not a MINT ERROR.
As Paddy said, looks like the coin was exposed to a sulfuric environment, reminds me of a end of roll coin.
It may have been popped out of a coin folder. Oxidation on one side but not the other. Pretty extreme example though.