50 Cents - Elizabeth II 2nd Portrait - Captain Cook

Struck to mark the bicentenary of Cook's 1770 voyage along the Australian eastern coastline, this was Australia's first commemorative fifty-cent piece — and notably, the first Australian coin to abandon the dodecagonal shape that had defined the fifty-cent denomination since decimal introduction in 1966. The switch to round brought it in line with international vending machine standards, a pragmatic concession that quietly ended the scalloped format for good.