100 Dollars - Elizabeth II 3rd Portrait - Koala - Platinum

Australia's platinum koala series launched in 1987, making Perth one of the earliest government mints to issue a platinum bullion coin for international investment markets — trailing only the Soviet Union's platinum Palladium issues and the Isle of Man's noble by a few years. The timing was deliberate: platinum was trading at a significant premium to gold through much of the late 1980s, and Perth was competing directly with the South African Krugerrand market that had been badly damaged by apartheid-era sanctions.

The third portrait of Elizabeth II, by Raphael Maklouf, was adopted by Australian coinage in 1985.