Generally speaking, the following are descriptions of the RAM's Mint Marks:
MINT MARK - RAISED C - No surround - RAM
Available from RAM & Coin Dealers etc.
COUNTERSTAMP - INCUSED Circle surrounding Raised Letter - Portable Press
Only available at ANDA Shows & Royal Easter Show, Sydney.
PRIVY MARK - Square surrounding INCUSED Letter -RAM
Readily available from RAM & Coin Dealers etc.
I'm not sure if the 'Privy Mark' is still being used. I don't buy much from RAM, so it may be in use, just that I don't see much evidence of it.
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