50 Dollars - Elizabeth II 3rd Portrait - Koala - Platinum Bullion Coin

Australia's platinum koala series launched in 1987, making Perth one of the earliest sovereign mints to issue platinum bullion coins for the international investment market. The third portrait of Elizabeth II — sculpted by Raphael Maklouf — was used on Australian coinage from 1985 until it was replaced by Ian Rank-Broadley's effigy in 1999. The 1992–1993 issues fall squarely within the Maklouf years.

Platinum spot prices were unusually volatile during this window, with the metal trading well above gold through parts of 1992 before a sharp correction tied to reduced industrial demand from the automotive catalyst sector.