Mint Marks On Australian Coins
And Die Varieties
Australian pre decimal coins have been struck at a
number of mints both in Australia and abroad.
To help identify from which mint a coin originates each mint adds a mark to the
coin different from other mints. The mint mark is usually located near the date
on the coin. There are some exceptions to this which are noted as they arise.
Mint marks on gold sovereigns:
M - Melbourne Victoria
S - Sydney New South Wales
P - Perth Western Australia
On both 1/2 sovereigns and full sovereigns with the St. George reverse the mint
mark appears on the lower side of the ground above the centre of the date.
Sydney mint 1/2 sovereign and sovereigns do not have a mint mark.
1/2 sovereigns minted between 1871 and 1887 with the shield reverse have the
date on the obverse and the mint mark on the reverse under the shield.
Full sovereigns minted between 1871 and 1887 with the shield reverse have the
date on the obverse and the mint mark on the reverse under the shield.
Mint marks on pre decimal copper coins:
H - Heaton Mint in London, England used on 1/2 pennies 1912, 1914 and 1915 and
pennies in 1912 and 1915 only. view
I - On the reverse just above the date indicates Calcutta, India. This was used
for 1/2 pennies in 1916, 1917 and 1918 and for pennies in 1917 and 1918.
I - On the obverse just below the Kings effigy indicates Bombay, India and
was used for both 1/2 pennies and pennies for the years 1942 and 1943. These
coins also have a dot before and a dot after the wording Half Penny and Penny
respectively.
Dots - One penny 1919 with a dot below the bottom scroll indicates Melbourne
mint.
One Penny 1919 with dot over the top scroll and dot below the bottom scroll
indicates Melbourne mint.
One Penny 1920 dot over the bottom scroll indicates Sydney mint
One Penny 1920 dot below the bottom scroll indicates Melbourne mint
One Penny 1920 dot over the top scroll indicates Melbourne mint
One Penny 1920 dot over the top scroll and below the bottom scroll indicates
Melbourne mint.
For 1/2 pennies A dot after the A of Australia indicates Perth mint
and was used in 1952 only.
A dot after the Y of Half Penny indicates Perth mint and was used in
1942, 1945, 1946, 1947, 1948, 1949, 1950 and 1951.
For pennies a dot after the A of Australia indicates Perth mint and
was used in 1952 and 1953.
A dot after the Y of Penny indicates Perth mint and was used from
1941 to 1945, 1947, 1948, 1950, 1951 and 1955 to 1964 inclusive.
PL - In 1951 some of our 1/2 pennies and some of our pennies were
minted at the London mint and this is indicated by a PL which
appears just after the Y of Half Penny and Penny respectively.
K.G - All pennies with a Kangaroo reverse, include as part of their
design the letters KG which appear in the field just above the
Kangaroos tail. Coins minted at the Perth mint during 1940 and 1941
have a dot between the K and the G distinguishing them as coins
struck in Perth. This dot is not always clearly defined and can
appear as anything from a clear dot to a low barely distinguishable
lump.
Mint marks on pre decimal silver coins:
H - Heaton Mint in London, England used on one shilling in 1915 and
florin in 1914 and 1915.
M - Melbourne mint used on the Threepence 1916 to 1921 inclusive,
Sixpence 1916 to 1920 inclusive, Shilling 1916, 1917, 1918 and 1920,
Florin 1916 to 1919 inclusive.
S - San Francisco Threepence 1942 to 1944 inclusive, Sixpence 1942 to 1944
inclusive, Shilling 1942 to 1944 inclusive, Florin 1942 to 1944 inclusive.
D - Denver Threepence 1942 and 1943 only, Sixpence 1942 and 1943 only.
PL - Royal Mint, London, both Threepence and Sixpence for 1951 only.
Dot - Before the S of shilling denotes Perth mint for the year 1946
only.
Star - A "*" above the date of the 1921 shilling denotes Sydney
mint.
Die variations and their importance
The following lists die varieties in order of decreasing
importance. The ranking represents my own opinion so feel free to disagree.
Master die type
A change in master die type represents a variation in the design of a coin.
Sometimes the design change is really obvious, such as the shift from lettered
reverse to the kangaroo reverse on the 1939 halfpenny. Other variations may be
much more subtle, such as the London and Calcutta obverses on the George V
pennies.
Mint mark
Identifies the mint at which a coin was struck. Often this is the sole
distinguishing feature.
Overdate
Coin struck with a die bearing traces of an earlier date. (See separate
discussion.)
Date numeral shape and/or position
A very common practice in die preparation was to use a partial-date working
punch to make coining dies to which the remaining numeral(s) were added by hand.
For small mintages this was considered more practical than making a derivative
master die and then a new working punch. The shape of a numeral may vary
depending on which particular tool the engraver used and the position of the
hand-punched feature on every working die is likely to be slightly different
from its peers although the differences may be microscopic. Collectors and
numismatists have tended to be dismissive of these variations but in my opinion
they are important. Conceivably, a diligent collector with the means to
distinguish these slight variations could identify each working die and
associate any given coin with a particular die.
Mint mark position
Mint marks were frequently added by hand to working dies and so are subject to
the same sorts of variation as for date numerals.
Re-entered features
Sometimes a working die may be worn or weakly formed but not so badly as to
justify discarding it. The engraver may decide to enhance a letter or numeral by
re-punching it and sometimes traces of the old feature are visible.
Doubled (or tripled) dies
When preparing a die from a puncheon in a hobbing press, more than one strike
may be necessary. Between strikes the die is removed from the press for
annealing and has to be realigned with the puncheon for the ensuing impression.
The realignment is done by hand and if it is not exact, traces of an earlier
impression may be visible, offset slightly from the later impression. Usually
such dies are never put into service but there have been a few instances where
the fault has apparently been unnoticed or ignored.
The foregoing remarks apply to Australian Commonwealth and earlier coinage. The
modern, hydraulic hobbing press used at the Royal Australian Mint for today's
coinage can produce a die or punch in a single pressing.
Cracks
The grain of the metal in die steel runs perpendicular to the coining surface.
While this yields a die resistant to compressive deformation, there is a
tendency for the die to split. It is a bit like hitting the end of a piece of
wood with a hammer. Eventually the die may disintegrate altogether but meanwhile
the crack produces an irregular raised feature on hundreds or thousands of
coins.
Modern dies are made of sintered alloys with isotropic grain, less prone to
cracking even when used on the harder materials comprising modern coins.
Nevertheless, cracks can and do occur.
Fills
Small features on dies such as mint marks and serifs can become filled with
metal from the coin blanks, thereby obliterating or diminishing part or all of
the feature.
Blobs
A hard impurity in a blank can dent the surface of a die and subsequent coins
will show a relief image of the offending speck.