What exactly went wrong in the manufacturing process to give these coins such a hefty price tag?
"The observe of some of the 2000 $1 dollar coins had been minted using the Australian 10 cent observe die by mistake," the ACCB explains.
"With just a 1.4 millimetre difference in diameter between the 10 cent and $1 coin the error went unnoticed, and the legendary 2000 $1 'mule' was released into the wild."
The ACCB conceded that the ultimate value of a coin would be decided by the buyer, so if you're hoping to snag an $8k sale you might be waiting a while. But here's some motivation to keep you going: this coin sold for $1,500 earlier this month.