The 1966 circular, .800 fine silver Australian 50 cent coin .
It was introduced on the 14th of February 1966.
The Royal Australian Mint in Canberra struck over 36 million 50 cent pieces however rising silver prices halted production. The Mint announced in late 1967 they were no longer releasing them into circulation.
The silver 50 cent piece was replaced with a copper-nickel dodecagonal (12 sided) issue in 1969, no fifty cent coins having been minted for 1967 or 1968, although the 1966 dated 50c were still being made in 1967.There is very little difference (0.2 grams) in the amount of silver in the pre-1946 florins and the 1966 50c.