Only 1 million 50c coins were again produced in 1993. Australian coin expert Joel Kandiah told Yahoo finance that the 1985 50c coin was Australia's 'joint rarest 50c coin' because of its low mintage.

Secret code hidden in new 50c coin released this week A new Australian 50c piece released today comes with a hidden code only the sharpest of people will be able to crack.

Aussies are being urged to check their pockets for a rare 50c coin that could be worth almost $15,000.

The Royal Australian Mint is releasing three new 50 cent coins. Instead of the usual silver, they will be gold.

A “very rare” 50 cent coin and 10 cent coin are set to sell for up to $1,500 each, with one expert urging Aussies to check their change for the chance to cash in.

Would-be spies have been challenged to crack the code engraved on the back of a new 50c coin, which has been issued to celebrate the 75th anniversary of an intelligence agency.