A bronze coin (30.8 mm diameter with plain edge) featuring a crowned and robed bust of George V facing left; around, GEORGIVS V D.G. BRITT: OMN: REX F.D. IND: IMP: ; below bust in small lettering the artist's initials B.M. The reverse features, within a circle of beads, the words ONE PENNY in two lines between upper and lower ornate scrolls; around the circle of beads, COMMONWEALTH OF AUSTRALIA . 1920 . There is a small dot below the lower scroll.
The dots on the 1919 and 1920 pennies were part of a series of tests on die steels that were undertaken at Melbourne. Dies were supplied to Sydney from Melbourne and it is argued that the steel marks can sometimes reflect the mint which produced the coin. According to the Australian Coin Chart 1966, the "Dot above top scroll" variety was minted at the Melbourne Mint and the "Dot below scroll variety" at the Sydney Mint. There is no indication as to the other varieties.
Sydney did not "mark" bronze planchets before striking at that time and had difficulty with the clarity of the rim (as illustrated in the photo below).
Master dies (London or Indian obverse) are judged by the alignment of letters and rim beads. Most catalogues however do not distinguish varieties based on different obverse.
Greg McDonald's Guide to Australian Coins and Banknotes lists the Proof variety as "Dot above top scroll" only.
The varieties listed below comprise all of the known 1920 Australian one penny coins (i.e. there is no "regular" coin which is not listed as a variety).