🙂 The mint error that causes the wood grain look is called: "IMPROPER ALLOY MIX"
🙂 Improper alloy mix happens when 2 or more metal alloys that are used to make
the coin simply didn't get stirred together well enough and so the end result is
this cool looking wood grain look on the coin.
🙂 You can read all about the IMPROPER ALLOY MIX ERROR at the following web
site:
https://www.error-ref.com/?s=IMPROPER+ALLOY+MIX