An Australian 1917 bronze Halfpenny (George V), uncirculated and in absolute mint condition could fetch up to $480 AUD. If it has been circulated but still in good condition, it might fetch anything from $0.75 to $70 AUD.
There were 5.760 million minted.
A reputable coin dealer will be able to give a more accurate valuation.
There were was no Australian 1956 Halfpenny minted.
The last Australian Halfpenny was minted in 1964.
The last Australian Halfpenny was issued in 1964.
The last Australian Halfpenny was minted in 1964.
Any Halfpenny coins circulating in Gibraltar in 1917 would have been British Halfpenny coins.
The Royal Australian Mint produced no Australian Halfpenny coins from 1956 to 1958 inclusive.
The Royal Australian Mint produced no Australian Halfpenny coins from 1956 to 1958 inclusive.
There were no Australian 1937 Halfpennies minted.
There were no Australian Halfpennies minted from 1956 to 1958 inclusive.
There were no Australian Halfpennies minted from 1956 to 1958 inclusive.
There is no Australian 1921 Halfpenny with a spurious "E" on it. You may have a genuine oddity. A reputable coin dealer will be able to assist with verification and give a valuation.
An Australian 1942 Halfpenny minted in Melbourne, has no mintmark. An Australian 1942 Halfpenny minted in Perth has a dot (.) after the (Y) in PENNY (PENNY.). An Australian 1942 Halfpenny minted in Bombay has an (I) below the King's head.