The Australian fifty cent piece as first put into circulation with the introduction of decimal currency in 1966 and continues to be circulated today. In its first year the coin was issued on a round planchet with quite substantial silver content. This type was quickly abandoned due to the expense of the silver content and confusion between it and the new decimal twenty cent. The first dodecagonal type (1969 - 1984) featured the Arnold Machin portrait, the second (1985 - 1997) featured the Raphael Maklouf portrait, and the third (1999 - present) features the Ian Rank-Broadley portrait. Throughout all of these types the obverse has remained Stuart Devlin's interpretation of the Australian Coat of Arms. In addition to these standard types a large variety of commemorative types have been issued. These commemorative types have preserved the now iconic dodecagonal planchet.