During the dark years of World War 2, Australia continued to mint coins, but some coins were minted by our allies.
In 1942, the following Australian Coins were minted -
Halfpenny
0.72 million minted at the Melbourne Mint
4.334 million minted at the Perth Mint
6 million minted at the Bombay Mint
Penny
12.244 million minted at the Perth Mint
9 million minted at the Bombay Mint
Threepence
0.528 million minted at the Melbourne Mint
8 million minted at the San Francisco Mint
16 million minted at the Denver Mint
Sixpence
8.968 million minted at the Melbourne Mint
4 million minted at the San Francisco Mint
12 million minted at the Denver Mint
Shilling
2.92 million minted at the Melbourne Mint
4 million minted at the San Francisco Mint
Florin
18.07 million minted at the Melbourne Mint
6 million minted at the San Francisco Mint
Any 1942, 1943 or 1944 Australian Threepence, will have the "S" (San Francisco) or "D" (Denver) mintmark on the reverse of the coin, on the right hand side, just below the fourth digit of the year. Any coins minted in Melbourne will have no mintmark.
There were no Australian coins minted prior to 1911. With the possible exception of traders tokens (with the traders business name on them), there were no "Australian" coins minted prior to 1910. The only coins circulating in Australia prior to 1910 were British coins.
try ebay
Halfcrown coins were never minted in Australia.
The Australian 1942 Threepence was minted at one of three mints. The 800,000 coins minted at the Melbourne Mint have no mintmark. The 8 million coins minted at the San Francisco Mint have a small "S" on the reverse below the units digit of the year. The 16 million coins minted at the Denver Mint have a small "D" on the reverse below the units digit of the year. The same applies for all Australian 1943 Threepences.
Most Australian Penny coins minted at the Melbourne Mint will have no mintmark. It is easier to identify those not minted at the Melbourne Mint. Pennies minted at the Perth Mint from 1938 will have a (.) after the Y in PENNY (PENNY.) or after the last A in AUSTRALIA (AUSTRALIA.) or between the KG above the kangaroos tail (K.G), depending on the year. Some of the 1951 coins were minted at the Royal Mint London and have a small "PL" after the "Y" in PENNY. Some of the 1942 and 1943 coins were minted at the Bombay Mint in India and have a small "I" below the bust of King George VI. The pre-1938 coins (before the kangaroo design) are a lot more difficult. Coins from 1911 and 1913 to 1914 and some 1915 were minted at the Royal Mint London and have no mintmark. Coins from 1912 and some 1915 were minted at the Ralph Heaton Mint in Birmingham and have an "H" mintmark below the scroll. Coins from 1916 to 1918 were minted at the Calcutta Mint in India and have an "I" mintmark below the scroll. From 1919, all coins were minted in Australia. The 1919 and 1920 coins may have a dot (.) above or below the scroll. A dot above the scroll indicates the Sydney Mint, a dot below the scroll indicates the Melbourne Mint. From 1921 to 1936, any Penny without a mintmark may have been minted at any of the Melbourne, Perth or Sydney Mints.
All 1966 Australian 50 cent coins were minted in Canberra. They have the distinction of possibly being the most hoarded coin in Australia.
Since 1984, all of Australia's general circulation coins have been minted at the Royal Australian Mint Canberra. Prior to 1984, Australia's decimal coins were minted at the Royal Australian Mint Melbourne and the Royal Australian Mint Perth as well as the Royal Australian Mint Canberra. Very occasionally, some have been minted overseas at the Royal Mint London, the Royal Mint Wales and the Royal Canadian Mint.
No lead 1 cent coins were ever struck by the US. Zinc coated steel cents were struck in 1943 only.
Dollar, Quarter, Dime and half-dollar coins from before 1965 are silver, as are nickels minted from 1942-1945 with a large mintmark over the Monticello.
Other than British gold coins such as the Half-Sovereign, Sovereign, etc., Australia has never produced "Australian" gold coins for general circulation in Australia. The Sovereign coinage minted for Britain were minted to the British pattern from gold mined in Australia and were minted at either of the Melbourne, Perth or Sydney Mints (Mintmarks M, P or S respectively).
Decimal Currency commenced in Australia on the 14th of February, 1966, the day the 1 cent coin became the basic unit of our currency. The coins were actually minted in 1965 in the Melbourne, Perth and Sydney Mints. Coins minted for the release of Australia's decimal currency included the 1, 2, 5, 10, 20 and 50 cent coins.