2007 Double Headed 5c piece
In 2009 a small number of double-headed 2007 5c pieces were reported to have been found in circulation. Double-headed or double-tailed coin errors are rare in Australia and are generally of unknown provenance, so it was unusual that multiple examples were found, and that they were found in circulation.
All known examples seem to be struck with coin alignment (the obverse and reverse are rotated 180 degrees) rather than medal alignment, much like other Australian double-headed and double-tailed coins. Most known examples appear to be circulated as well. While there is general skepticism around such errors being true accidents, the 2007 double-headed 5c has a better appearance than most of being a true accident, though it is believed that configuring coining presses to strike double-headed or double-tailed coins is exceedingly difficult, so it is more likely than not that they are fabricated errors.
There have been a number of sales over the years: lot 464 in IAG auction 71 in March 2010, lot 115 in Noble auction 96 in April 2011, lot 89 in Noble sale 109 in July 2015, lot 604 in Noble auction 112 in July 2016, lot 114 in Noble sale 114 in March 2017 and lot 93 in Noble auction 122 in November 2019. PCGS has also graded a number of examples including 45594023.