The Australian 20 cent coin was first introduced with decimalisation on 14 February 1966 when it replaced the pre-decimal Australian florin, to which it is equal in size and mass. The original reverse design by Stuart Devlin has not been changed since its introduction.
The denomination is occasionally used by both the Royal Australian Mint and the Perth Mint to issue collector coins, which are legal tender in Australia - such as this one.
In 2010, the Royal Australian Mint produced - apart from the regular brilliant uncirculated, proof and silver proof coin sets - a commemorative gold coin set, the 2010 Gold Proof Set - Australian Numismatic Centenary. Unlike the other sets - which feature the regular effigy of the Queen by Ian Rank-Broadley, which was in circulation in Australia at the time - the coins in the gold set have her effigy by Vladimir Gottwald.
It is a uniquely Australian effigy, designed exclusively for the Royal Australian Mint, by its world renowned designer - Vladimir Gottwald. Acting on a worldwide invitation from Buckingham Palace in 1999, to design a more modern effigy of Queen Elizabeth II, Vladimir Gottwald’s design was eventually selected to honour Her Majesty’s royal visit of 2000 on a commemorative 50c coin.
The 6-coin set contains 5 cents, 10 cents, 20 cents, 50 cents, $1 and $2 coins - all with the Queen's portrait by Vladimir Gottwald.
The coins are made of 99.99% gold. No coins of this type were released into circulation. | 
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