Modified coins have no collector value. Any value would be associated with the ring.
There were no Australian 1937 Halfpennies minted.
Modified coins have no collector value. The ring may have some value.
Such a coin does not exist. Canada has not used the British sterling currency system since the mid-19th century, and has never issued a Halfpenny or half cent coin since Confederation. If the coin has no country name on it and has a sailing ship on the reverse, it would be a British Halfpenny. Alternatively, you may have a privately minted Halfpenny token.
There were was no Australian 1956 Halfpenny minted.
An Eireann (Irish) 1937 bronze Halfpenny (pig), uncirculated and in absolute mint condition could fetch up to £50 GBP. If it has been circulated but still in good condition, it might fetch anything from £2 to £12 GBP. An Eireann (Irish) 1937 bronze Halfpenny (pig)(Proof FDC), uncirculated and in absolute mint condition could fetch up to £400 GBP. A reputable coin dealer will be able to give a more accurate valuation.
The last Australian Halfpenny was issued in 1964.
The last Australian Halfpenny was minted in 1964.
The last Australian Halfpenny was minted in 1964.
There was no 1948 New Zealand Halfpenny minted.
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 Halfpenny has never been minted in silver. If you have a "silver" Halfpenny, it is possibly because somebody has silver plated it. Modified coins have no collector value. For future reference, please provide a year.