15 Dollars - Elizabeth II 4th Portrait - Platypus - Platinum Bullion Coin

The Perth Mint's platinum platypus series launched in 1988 as one of the world's earliest platinum bullion programs, competing directly with the Canadian Maple Leaf and the Isle of Man Noble for institutional and collector buyers. By 2010, platinum had retreated sharply from its 2008 peak above $2,200 per troy ounce — a collapse driven largely by the automotive sector's demand destruction during the global financial crisis, since roughly half of annual platinum consumption goes into catalytic converters. The fractional weights in this series were issued in strictly limited quantities relative to the one-ounce coins, making survival in pristine condition dependent almost entirely on storage rather than chance.