There's a wealth of information located on the Internet, you just have to know where to look! Google plays a major part in that, and this website stands out quite prominently in Google searches for the articles that we've written. Over the past year or so our website of important numismatic information has grown well beyond what we'd ever imagined it would. It contains valuable, well researched information on a variety of topics from issues and mintages, errors, varieties, collecting coins, storage options and investing in coins and so on.

We get many emails from the readers and Googlers asking advice about coins they've found, inherited or are interested in finding out more about.

Remember the forum aussiecoins.net? This was a great avenue for collectors and dealers to post valuable information about news, views, current events and happenings in the numismatic world. One day, that forum, just disappeared! All the information was lost without warning. From it's demise other forums have spawned such as www.acbo.com/forum* but one can't help be upset over the loss of such a vast amount of valuable information contained on the original forum site.

Through the growth of online publication, the National Library of Australia has seen a need to find important online resources and archive them so they can never be lost. This secures the valuable information so it can be useful to everyone for the infinite future. This National Library archive is known as Pandora and the www.australian-coins.com website which incorporates the weblog has now been archived for the benefit of all in the future.

The archived information for this website can be viewed on the Pandora Website. This information will be re-archived annually to catch up on new articles and adjusted information throughout the site.

Now that the website has been stored by the National Library in the Pandora archive the information it contains can never be lost!

*edit September 2012 What do you know the ACBO forum has also collapsed. Please visit The Australian Coin Forum.

Australia 1970 50c, Left: Normal 7, Right: Tilted 7

A few months back we posted up an entry about the Australian 1970 50c Captain Cook 50c. A sharp eyed reader suggested we should have mentioned the 'tilted 7' variety of this coin, and now that we have a flash new USB microscope we feel we can do this variety some justice.

The 'tilted 7' variety of this coin, as you would expect, shows a tilted 7 in the date. Seen above you can see the normal variety of the coin on the left, with the top bar of the 7 more or less lining up with the top of the 9 in the date. On the right you can see the tilted 7 variety where the top bar of the 7 clearly points some distance above the top of the 9 in the date.

We've got no real idea as to the frequency of the tilted 7 with respect to the normal 7 coin (but we only found 1 tilted 7 among the 10 or so 1970 50c coins we had on hand), so any information regarding this would be appreciated. The only way we can imagine the tilted 7 coming about is via a hand punched working die, or perhaps a reworked master die that was used to produce hobs with the tilted 7. But of course this is pure conjecture and again any information from our readers would also be appreciated.

A well known Australian decimal variety expert mentioned recently on the Australian Coin and Banknote Forum* that not only does the reverse of the 1966 20c coin show distinct mint marks, but also the obverse die shows differences between coins minted in London and those minted in Canberra. Immediately thinking, here's an opportunity to make use of our new Dino-Lite USB Microscope we thought we'd take a look at this. Unfortunately the author of this entry only had several low grade London and Canberra 1966 20c coins to work with so the investigation was confined to comparing the size of features on the obverse of the coin. We plan, at a later date, to image high grade coins from both mints to see if there are any die feature differences between the two mints.

Firstly, it is apparent that Canberra minted coins have slightly thinner obverse rims and the lettering of the legends is closer to the rim. This is shown clearly in the image below:

Australia 1966 20c LIA Detail, London Mint Left, Canberra Mint Right

You can see a detailed micrograph of the LIA of Australia with the London minted 1966 20c coin on the left, and the Canberra coin on the right. The lettering is noticeably closer to the edge on the Canberra coin. The next task was to look at the size of HM's portrait to determine if the lettering was simply spaced differently on the two dies or to determine if the die on the London coins was a 'small obverse' and that on the Canberra coins a 'large obverse'. You can see the results below (including magnified cut-outs to show detail).

Australia 1966 20c Obverse Detail, London Mint Left, Canberra Mint Right

It is readily apparent that the portrait of the London minted coins is significantly smaller than that of the Canberra minted coins. One can only wonder how this could have happened. For a difference in the size of the dies use to produced the machines one would think that an (ever so slightly) different reduction ratio was used on the reduction lathe which is used to produce master steel dies from the relief model of the coin design. These master dies are used to produce working hobs which in turn would have been used to produce the working dies that actually minted the coins.

We'll be doing some further research into this to try to shed some more light on the subject. Stay tuned.

*edit 9/9/12 The Australian Coin and Banknote Forum is now inactive. Please visit the The Australian Coin Forum

PVC Residue on Coins

Have you seen coins like this for sale, in dealers stock books at shows, in public auction lots, eBay items or even coins in your own collection? These coins are the extreme but if your coins are stored in pvc then this is what will happen. Not might happen, will happen! These coins are affected with pvc residue from storage in pvc album pages or pvc plastic bags. Underneath the green slime the coins are pitted and eroded by the chemicals in the pvc residue. These coins have been permanently damaged.

Maybe you have coins that aren't this bad. PVC residue can first start to show as a cloudy or milky haze over the coin surface, a greyish film, maybe a slight green tinge in the right light. The coins might even feel slimy to touch such as those from early decimal mint sets that have been stored in their original pvc packaging.

PVC is the abbreviation for poly vinyl chloride, a material used almost everywhere in your home. It's a hard plastic and to make it useable into soft plastic album pages, plasticisers are added. These plasticisers contain a whole aray of harsh chemicals and the pvc itself contains 30% cholorine, a bleaching and corrosive agent.

When these chemicals come into contact with your coins the acidity cycle starts. PVC isn't heat tolerant and will start to break down even before it leaves the factories. These chemicals will leach out of the plastic, even through your mylar 2x2 and onto the coin surface.

You can usually identify PVC by the ghastly odour it emits, like a cheap plastic childs toy. That's the chemicals leaching already.

PVC residue can be removed with some careful attention and acetone, but the damage has been done. Third party grading services won't slab your coin if it exhibits pvc residue or damage and if you've cleaned it then it won't get a grade either. Your once valuable coin......just lost a lot of it's value.

An article here by Scott Travers is also well worth a read.

The problems with PVC have been known for many years now.

Letters to the Editor.
Sir, - I have a plastic coin album containing plastic coin and note sheets and some of the coins in the album are getting a green tinge.
Most of the coins showing the green colour are silver coins, 2/- pieces and the 1966 fifty cent pieces, also a few 1/- pieces and even some pennies......Some of the coins in the album have been cleaned, but certainly not all that are getting the green tinge.
Could any of your readers advise the cause of this discolouration and how it is prevented. - Yours etc. I.C. Gilbert Jerilderie, NSW
The Australian Coin Review December 1971.

The coin below is a magnificent double struck 1952 shilling. It has one major problem though. It has been stored in PVC. I purchased this coin because such a coin is a rarity and very valuable. It was delivered covered in a green film (not as bad as those pictured above). After an acetone bath the damage was clear. See the surfaces of the coin aren't smooth? The surfaces of the coin have been eaten by the PVC chemicals causing permanent damage. This coin wouldn't get slabbed by PCGS, it has been permanently damaged by the storage method that was supposed to keep it safe and preserved. It has in fact been ruined and lost probably half of it's value as such.

Safer alternatives to PVC flips or PVC album pages are those made from proven safe plastics such as polypropylene, polyethylene or polyethylene terephalate. I know that's a jumble of long words but your coins are valuable and storage is of the utmost importance. Before buying any coin accessories why not ask your seller, "What are these accessories made from?" If they don't know, walk away. Do your research and make informed decisions. An honest seller should be forthcoming with information, and if they aren't or can't be specific then move on to someone who can.

Permanent PVC Damage