Australia 2000 20 Cent Partial Collar Error

Over the years we’ve seen a number of year 2000 20 cent coins that were struck incorrectly, usually they’ve been tilted or straight partial collar errors. Above you can see an image of one such coin that is a bit different (and quite a bit nicer) than most such errors. Firstly, and most obviously it’s a fabulous grade. In fact we’re told it was removed directly from a mint bag and placed into a coin holder almost 16 years ago which helps explain how it’s still in such excellent condition. Looking closely at the image above the keen eyed observer will note the coin shows a thicker rim that you’d expect around about half of the coin, while about a quarter of the rim is simply missing.

An examination of the edge of the coin (see below) shows that the coin barely engaged at all with the collar and reeding is present on only a small fraction of the width of the coin edge. There’s actually only a trace of reeding present on 3/4 of the circumference of the coin, with no reeding at all visible the remaining on 1/4. The area of missing reeding corresponds with that region on the obverse running from the top of the Queen’s tiara around to I of Australia. It’s no coincidence that the area of missing reeding is also the same region of the coin that is missing any sort of rim.

Partial Reeding and “Ghost” Reeding

If you look closely at the detailed image above and that below you’ll see what we’re calling “ghost” reeding on the coin edge above the area of fully formed reeding. This “ghost” reeding is barely formed and could easily be mistaken for scratched on the coin edge but careful examination shows that lines match up perfectly with the indented parts of the fully formed reeding below. We can’t recall ever seeing this feature on an error before and can only postulate as to the cause. The most likely explanation is that the blank was partially engaged with the collar die prior to being struck and as it was struck it tilted upward and scraped against the collar die leaving the faint witness marks of this movement.

“Ghost” Reeding

One of the strongest indicators for the authenticity of most out of collar or partial collar coin errors is unconstrained radial metal flow. Usually the collar die constrains the radial metal flow of a coin blank and indeed forms the edge graining/reeding of the coin as the flow is restricted. However, when a bank fails to engage with the collar the metal of the coin planchet flows outwards. This metal flow is generally visible in a few different ways. The first is “fish tailing”, a second (and less common) observable characteristic are radial metal flow lines. The images below show both these characteristics. A concavity is present in the base of the L of AUSTRALIA due to the metal in the upstroke of the L flowing radially outward.

Fishtailing on the L of AUSTRALIA

This second image shows the radial metal flow lines around the T of AUSTRALIA. The lines run directly from the center of the coin to the circumference of the coin. They are particularly evident in the image below because this is the region of the coin that failed to have any engagement with collar die at all.

Metal Flow Detail

Conclusions

The year 2000 is one of the more common years to find mis-struck 20 cent coins, particularly partial and tilted partial collar errors. The coin discussed in this article is much nicer than most as it was withdrawn from circulation very early in it’s life. It has most of the strong indicators that an error collector should look for when determining the authenticity of an error coin including partial reeding, fishtailing of legends, and radial metal flow lines. It also has an interesting feature not often seen, so called “ghost” reeding, perhaps formed as the coin blank moved in the collar die as it was struck.

1981 Double Struck Partial Brockage 20 Cent Error

Above is an error coin that is an interesting combination of two error types. It’s a partial brockage, having been struck against another already struck coin, and it’s also been struck twice, making it a double struck error. Either of these types of errors is rare on any Australian decimal coin but to find both on the same coin is truly unusual.

Partial Brockage Detail

Partial Brockage

Above you can see a detail of the area of the coin showing the clear partial brockage with a reverse impression of the letters ELIZ from another already struck coin. The sequence of events that resulted in this error were probably something along these lines:

1. A blank enters the coin press and is struck as normal.
2. The struck coin is ejected from the coin press incorrectly and remains partially within the coining chamber of the press.
3. Another blank is fed into the collar die.
4. The press strikes the blank coin but because the first struck coin is still within the coining chamber an impression of that coin is struck onto the new blank coin resulting in the partial brockage.
5. Because of the obstruction (the already struck coin), the collar die which is spring loaded is forced downward when the blank coin is struck resulting in only partial engagement with the collar. This is indicated in the image below, which shows only partial reeding on the edge of the coin which is the result of partial collar engagement.

Incomplete reeding indicates partial collar engagement

Double Strike

This error coin has also been double struck while partially retained within the collar which is sometimes known as a “rotated double strike”. Interestingly it was also struck twice against the already struck coin resulting in a double struck partial brockage. Indications of the double strike are a little more difficult to spot.

First, a close look must be taken at the legends on the obverse (Detail A), which you can see in the image below. They have the typical spidery appearance that is the result of the planchet shifting slightly between strikes. Secondly on the reverse you can see clear doubling of the beak of the platypus (Detail B) and finally the partial brockage itself clearly shows two impressions of each letter (Detail C).

Click image to enlarge

Conclusions

Decimal coins are very collectable right now, and double struck or coins with brockages especially so. This coin is a nice combination of both these types of errors, and arguably is a partial collar too, making it a combination of three error types. It’s extremely unusual, and the first time the authors have seen a double struck brockage on an Aussie decimal coin. An interesting though exercise is the visualize the other coin involved in this process, it’s been struck three times on the reverse, once correctly and twice offset significantly. The obverse has been struck correctly once and then offset and struck against this error coin twice. A reasonable classification for the other coin would be a “partial offset die cap”.

As something of a footnote it’s very common to see these sorts of spectacular errors (whether pre-decimal or decimal) with some form of gouge on them. Presumably put there by a mint worker with some sort of metal tool (perhaps a screwdriver) trying to remove the offending item from a jammed coin press. This coin is no different, with a decent sized scrape on the 0 of 20 perhaps put there 35 years ago by a possibly frustrated mint employee!