2 Dollars - Elizabeth II 4th Portrait - Mini Koala, Gold Bullion Coin

The Mini Koala series was Perth Mint's calculated entry into the fractional gold bullion market, targeting collectors priced out of full-sovereign formats. At half a gram, it sits at the absolute lower threshold of practical gold coinage — any smaller and manufacturing tolerances would make consistent fineness impossible to guarantee. Perth's reputation for .9999 four-nines purity was itself hard-won; the refinery only achieved that standard commercially in the 1980s, distinguishing it from most government mints still working at .999.

Ian Rank-Broadley's fourth portrait of Elizabeth II, used here, was already being phased out globally by 2015 in anticipation of Jody Clark's fifth effigy — making late fourth-portrait issues quietly transitional.