This is part 2 of a series on rare decimal coins that can be found in Australia. Interesting and extremely rare Australian decimal coins include the 1981 scalloped 20 cent which is a 20 cent design accidentally minted on a Hong Kong $2 planchet, there are 6 examples of these known to exist.
Occasionally a coin of a different year finds it’s way into a years mint or proof set. In a very few examples of the 2006 proof set it has been found that the dollar included was a 2005 mob of roos coin. Although it has not been officially recognized by the Royal Australian Mint it is a clear error, as there were no other 2005 proof mob of roo dollars released. The proof dollar minted for the 2005 set was the Dancing Man dollar. This Mule is definitely a rarity with only around 40 known sets to date.
A possibly unique error that surfaced at a Downie’s auction in 2007 was a bi-metal 20 cent piece. This was said to have been removed from an Armaguard security roll. The only practical explanation for this is that a foreign bi-metal blank got mixed in with a batch of our blanks which the RAM sources from Korea. This coin which cost it’s owner 20 cent was sold for $3600 + comm.
It is interesting when reading the RAM official mintage reports for each year, in 1988 a 50 cent Coat of Arms issue is just not mentioned. The issue for 1988 was the commemorative Bicentennial design. Surfacing in an IAG auction in August 2006 was just that, an accidental 1988 Coat of Arms coin selling for $5400 + commission. This has also happened in 1977 when the 50 cent was minted with a reverse design commemorating the 25th anniversary of the coronation of Queen Elizabeth. These coins can be officially labelled as mule error coins as they were struck from dies not intended to be paired together (for that year anyway).