Australia has been minting these neat 50 cent coins since 1966. Back then, they were round, but soon thereafter, in 1969, they took on the 11-sided shape:
50 CENTS DATED 1966: Round, made of 0.342 troy ounces of silver
50 CENTS DATED 1969 TO 1997: 11-sided, made of copper-nickel
These are large, interesting coins, and collectors enjoy them a lot. All of the 11-sided coins are worth only face value when they are worn or circulated, but some uncirculated specimens carry good numismatic (coin collector) value as explained below.
ROUND 50 CENTS DATED 1966:
average circulated: BV
well preserved: BV
fully uncirculated: BV + $5 US dollars
BV is 'base value' and is the value of the silver in the coin. If, for instance, silver is trading for $18 US dollars per ounce, BV = 0.342 x 18 = $6. Look up the price of silver. It changes every day.
11-SIDED 50 CENTS DATED AFTER 1966, except as noted below:
worn: less than $1 US dollar approximate catalog value
average circulated: less than $1
well preserved: $1
fully uncirculated: $3
If you have a fully uncirculated 11-sided coin, there are a few dates which stand out as more valuable than others. He is the list:
If your 11-sided coin is not in the FULLY UNCIRCULATED list, then it is worth the values shown under 11-SIDED 50 CENTS DATED AFTER 1966.
There are also proof coins made especially for collectors. We do not follow proofs on CoinQuest. Coin catalogs show them selling for as little as $5 and as much as $35, depending on date. Refer to a coin catalog if you have a proof coin.