The Australian Threepence was minted in most years from 1910 to 1964 inclusive.
Assuming they are in mint uncirculated condition, the most valuable coins not including pattern, proof or error coins would be -
1915 - $4,500 AUD
1942 - $3,700 AUD
1923 - $3,350 AUD
1914 - $2,650 AUD
1912 - $2,450 AUD
The collector value descends rapidly as the condition of the coin decreases.
The slang term for the Australian Threepence was "tray".
The last Australian threepence was struck in 1964.
An Australian 1925 Threepence minted at the Melbourne Mint will have a small "M" below the date.An Australian 1925 Threepence minted at the Sydney Mint will have no mintmark.
The Australian 1944 Threepence was no bigger or smaller than any other Australian Threepence. They were all 16 mm in diameter and weighed 1.41 grams.
The rarest general circulation Australian Threepence, as distinct from the most valuable, would be the 1942 Threepence minted in Melbourne of which there were 520,000 minted. The other Threepences minted in 1942 were minted in the San Francisco (mintmark = S) and Denver (mintmark = D) mints in the USA. Threepences from this period that were struck in Melbourne have no mint mark. All others will have a mint mark on the reverse below the fourth digit of the year indicating the city where minting occured.
There were no Australian Threepences minted prior to 1910.
As far as general circulation coins are concerned, easily the most valuable Australian Penny is the 1930 Penny and the most valuable Halfpenny would be the 1923 Halfpenny.
Such a coin does not exist. The Royal Australian Mint did not produce any Threepences in 1933.
There were no Australian Threepences minted prior to 1910.
dony
The first Australian coins to be put into circulation were the Threepence, Sixpence, Shilling and Florin in 1910.
With the possible exception of traders tokens (with the traders business name on them), there were no "Australian" Threepences minted prior to 1910.