50 Dollars - Elizabeth II 4th Portrait - Platypus, Gold Bullion Proof

The Perth Mint's .9999 fine gold standard, applied here, was a deliberate commercial challenge to the Royal Canadian Mint's then-dominant position in the four-nines bullion market. Australia had been producing .999 gold since the 1980s, but the push to .9999 fineness in the late 1990s was partly a response to collector and investor demand driven by Canadian Maple Leaf sales figures. The 2007 proof striking of this denomination sits in a transitional period for Perth's bullion proof program, when mintage caps were being tightened to sustain secondary market premiums.