The 1966 Wavy Baseline 20c is most likely our best known rare decimal Australian coin. The 20c Wavy is an absolute essential in a serious decimal coin collection. Production of 20c coins in 1966 occurred in Canberra at the Royal Australian Mint and in London at the Royal Mint. 28,196,000 coins were produced in Canberra and 30,000,000 in London. One of the dies that was used in London was slightly different to the rest. It produced a baseline at the bottom of the 2 on the Reverse that is curvy, and is paralleled in the swirl of water directly above it. This die has been researched and is only said to have produced a very small number of the Wavy Baseline 20c coins. It is popular belief that the die was repaired using a mini grinder before production leaving the wavy characteristic. Source: http://www.dollarmule.com.au/id10.html
