10 Cents - Elizabeth II 2nd portrait, Obverse Mule

The 1972 New Zealand 10-cent mule pairs the obverse die of the pre-decimal or mismatched series with an incompatible reverse, a production error that escaped quality control at the Royal Mint. New Zealand's decimal coinage had only launched in 1967, and the transition period left the mint managing multiple active die sets for several Pacific issuing authorities simultaneously — the conditions under which mule errors most reliably occur. Surviving examples are scarce precisely because they entered circulation undetected rather than being caught and melted.