1988 Coat of Arms Mule 50 Cent
A number of interesting mules have been produced at the Royal Australian Mint over the years, mostly in the 1970s. One mule produced in the 1980s saw the combination of a 1988 50 cent obverse die with a regular Coat of Arms 50 cent reverse. All circulating and mint set 1988 50 cent pieces were meant to have been produced with a commemorative bicentenary reverse. There is reported to be a single example in uncirculated condition (p135, McDonald, Pocket Guide to Australian Coins and Banknotes, 2014) but there may be others. The circumstances of its production are unknown but given that a single uncirculated example is known, it was probably a deliberate production on the part of mint staff not following procedure.
An example was sold as lot 487 in IAG sale 64 in August 2006 for $5,400 plus commission. The November 2019 Australasian Coin and Banknote Magazine reported that Downies sold an example to a private buyer for an undisclosed five figure sum.