How we detect fakes

A member of the CoinForgeryDiscussionList
https://groups.yahoo.com/neo/groups/CoinForgeryDiscussionList/info?yguid=116957790

lamented that members of that list condemned fakes but rarely explained how they knew a coin was fake. I took a shot at explaining the sorts of coins that were exposed. I reproduce my comments below and welcome your contributions. You can join that Yahoo group and set it to send you e-mail once a day (or not at all). You would average a few eBay sellers condemned each week.

My comments to the list members:

There are different degrees of deceptiveness in fakes. This list rarely uncovers the most deceptive. We mostly use two techniques. We recognize poor replicas and we recognize cast clones.
Those who made ancient Roman and Greek coins were amazingly good at what they did and you can, after a few years, recognize the the style which is remarkably consistent for any given issue. There are businesses who make "replicas" for sale in museum shops who don't need to reproduce the old style accurately. Parents buy them for kids at the shops. Criminals buy them and put them on eBay with some con-artist story. That level of fake is most of what we catch and report to CFDL and put on the blacklists.
If you want to be able to recognize that type of fake, study lots of genuine coins of any given type and when you see a replica it stands out as far from the norm.
A second type we can expose on this list is casts. Roman and Greek coins were not cast (with few exceptions). Casts may have perfect style, but casts are usually a bit "soft" like the difference between a new bar of soap and one that has been used. Modern casts can be superb and the best of those we don't catch those by noticing softness. We probably don't expose top-quality casts on this list. Most casts we do catch are pretty bad with "casting bubbles" or other typical signs of casts. They usually have "casting seams" around the edge (or file marks erasing the seams) which is why some sellers show a photograph of the edges of coins.
Another way we catch fakes is my noticing two identical coins. That is, identical except possibly for recently applied surfaces. Ancient coins were struck by hand. No two have exactly the same strike, flan flaws, and centering. If you can find two coins that are identical in enough ways, they are likely both cast fakes, although it is remotely possible one is the genuine "seed" and the other a cast from it. Sometimes you hear the term "clone" in this context. Criminals may tone one brown and coat another with sandy surfaces, so you must look beyond the color to see if they are "identical."
Here is a true anecdote. A man bought a Byzantine copper of a very specific type he collected. He had over 40 examples of one Sear-number type. This example was one of his favorites for being so nice. Then, another six identical examples were discovered. Same flan cracks, etc. Oops! All fakes! Even experts can be fooled by some fakes.
There are firms that openly make and sell very good replicas that are far more deceptive than museum replicas. But, they usually make only one die of any given type and if you can perfectly match a coin to their replica it is because it is one of their replicas. Many of these are illustrated at ForgeryNetwork
http://forgerynetwork.com/
(Ignore the search boxes for "class" "category" and sub-category" and just search on "Keyword(s)").
Perhaps a collector would like an example of an expensive Greek coin he cannot afford. He can buy a $10 replica to fill the hole in his collection. Or, he can buy a $10 replica and hope to sell it on eBay for a huge profit!
There are professional counterfeiters who worked in the past and whose fakes have been published. Match one exactly and the coin is a fake. We catch some, but not many of those. Many are illustrated at ForgeryNetwork.
There are professional counterfeiters who work in the present and whose fakes pass as genuine. I have heard of people buying excellent coins and reproducing them with 3D printers!
On this list we use photos on eBay to expose coins as fakes and sellers as fakesellers. Photos are not much information. It is not like inspecting a coin in hand. It takes a pretty poor fake for us to catch it. We don't usually explain why we think replicas are fakes because most are so far from normal style that they are "obvious." We do point out clones and try to note two examples when two coins are identical fakes.
If you want to learn how to spot fakes, go to the coins we identify. Compare the style to the style of genuine coins. Looks for signs of casting--especially "softness" or "casting bubbles" or a "casting seam". Look for "identical" examples at ForgeryNetwork. That's most of what we do to identify fakes.

 

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Nice summary, Warren. Thanks.

 

Sadly, I've gotten a first-hand lesson in many of these issues / techniques recently.

 

A very nice summary! Thanks

 

Thanks, Love it!!!!!!!!!!!!!!

 

Here is my limited understanding of a devious forgery technique.

A giveaway of the more sophisticated transfer die fakes is that they also reproduce the host coin exactly, including corrosion pits and other wear or damage that should be unique. The worst transfer die coins are restruck using new transfer dies on a worn out old ancient coin, so the metal and fabric of the coin are correct.

I got suckered when I bought a Himera bronze coin that is normally $6000 for $895. I did not research it enough to realize this was a really rare and valuable coin. They eye of the eagle is all wrong and the pitting on the body of the sea creature is reproduced on all examples. The vcoins dealer I bought it from did not know that either and immediately gave my money back. I have seen other copies of this same coin floating around so look out:



A famous transfer die forgery came up when the technology was relatively new. Someone faked some Syracuse dekadrachms and they made it into a major auction. Someone pointed out that the legs of the horses ended while there was still flan left. That is another giveaway of the transfer die, the devices end before the edge of the flan, because the host coin was off center.

John

 

Thanks for telling us!

 

Some other possible signs of transfer dies include stuttering of the devices near the edges(an artifact of pressing at high pressure versus striking) and occasionally these transfer die forgeries will have remnants of the undertype left around when they're pressed or struck on ancient flans. Some can be detected by simply considering whether or not it's possible for the type to be overstruck on a given undertype(i.e. undertype is newer than the type overstruck on it). Additionally, if the host coin used to make a transfer die was, itself, overstruck, it can transfer details of the undertype into the die. The orientation and appearance of an undertype on an overstruck coin relative to the new type should be as unique as the flan shape, strike and other characteristics that make all handmade coins unique and I am unaware of any known cases where an overstruck type somehow transferred its devices to a die, so one way to guard against such fakes when buying overstruck coins is by looking for other overstrikes for cases like this where the transfer die picked up the undertype.

 

Ugh. I still have one of these. Speaking to some recently they are saying they are genuine. I dont know what to believe. Anyone have links to the old threads? I spent half an hour looking but the searches came up empty. I'd like to see what the current consensus might be on these.

 

https://www.cointalk.com/threads/new-akragas-hemilitron.278898/

https://numismaticfakes.wordpress.com/tag/akragas/

And speaking of that blog, I wonder what happened to the site owner, CT member @Odysseus? His site hasn't been updated in over a year and a half.

 

Thanks @TIF. I saw those, but was hoping to find the thread where I posted my example and my own comments as well as others. Cant seem to find it. Like I said, some have said those Akragas might be genuine, but I'd like to review all the data, photos, comment, etc.

 

If they all have the corrosion pit in the body of the sea creature, they can't all be genuine. I found the original coin in some online catalog, can't remember which. It was clearly a spot of green corrosion. The fakes made from it have flan metal which replicates the size and shape of the corrosion spot, if that makes any sense.

 

https://www.cointalk.com/threads/fake-akragas-topic-again.285093/

 

Odysseus was sure several coins i posted wete fake from the photos. David Sear disagreed. Odysseus was an interesting guy but a little quick to condemn coins.

 

It’s a really interesting discussion! What is your opinion about fake gold coins (late Roman or Byzantine)? Are these fakes as comon as the bronze ones?

 

Forgive me if this is already covered here and I missed it, but another 'tool' I use for identifying possible 'fakes' is Size and Weight.

 

Although I have some late Roman/Byzantine gold acquired decades ago, it is not an area of current interest to me, so I avoid those pitfalls. But there are some very deceptive fakes out there. I would personally not buy any late Roman/Byzantine gold unless it were from an established dealer.

 

This might be fun... What is the MOST Decisively thing wrong with this coin?

 

The obverse legend is missing a typical COS at the end for the type?

 

Bingo! Took a while for someone to answer! Nice work Gavin!