How To Detect A Fake Coin

Thanks everyone for the contributions. I tried editing the original post with additional information but unable to do so. Perhaps moderators will allow me to edit ? So I will add few more information here for now.

This website below has a list of known fakes. However I am not sure how often this get updated or if someone verify the claims. But still very good information.
http://www.forgerynetwork.com/default.aspx

More information about spanish fake cobs,
http://www.sedwickcoins.com/fake_cobs.htm


Russian fakes,
http://www.rnumis.com/rnumis_resear...p_rf_gallery

I know recently we had a thread about fake British Gothic crowns where some wanted to have a thread just for reporting fakes on ebay. Perhaps if we can update this database, it would benefit everyone ?

More about diamagnetism and slide test here,
http://fakes.numismetrica.com/ident...ounterfeits/

Collonialjohn, I will definitely buy the book. I am very concerned about all the fakes out there as I buy most of my coins from ebay. There is another thread in the main coin forum discussing about even dealers passing the fakes with/or without the knowledge.

tokenmast, thank you pointing out the strength of the magnet. I have a N52 pickup magnet and thought I was all set. And I did the same War Nickel test and was shocked to see mine didn't picked up the nickel.. Now I had to get a set of N40s and retest every coin.


Pertinax, thanks for sharing the British museums free authentication service. We don't have such a luck here in US, everything has a price :)

So do I.


It seems someone has a knowledge about the strength of a magnet such as N40 and N52. I will read through this thread again and in the time being would anyone like to elaborate more about the strength of a magnet and tell how to buy an ideal magnet to check a fake coin out. I want to buy a magnet indeed. Henry

I consider it very worthwhile to have a specialist 'black' collection of fake coins.
My 'black' collection has about 100 fakes. Some of them are obvious with close examination, and quite a few of them are dangerously deceptive.

Most of them were acquired from two auction job lots, where they were described as fakes, but quite a few of them were acquired from a dealer who has the highest of reputations in the numismatic business in Australia. Those particular 'coins' were swapped for some genuine coins.
Normally, those coins would not be released by this particular auctioneer to a customer, but in my case, I have personally known him as a trusted friend for over 30 years. His trust in me is that I would not try to re sell them.

The dealer had acquired them from customers submitting coins for auction. In most cases, the customer who had intended to submit them for auction, had been told the sad news. In these instances, the intending seller had just surrendered the fake items to the auctioneer.

Having a collection of highly deceptive fakes and being to be able to study and test them, has certainly helped me in gaining very useful skills in being able to detect deceptively dangerous fake coins. Nevertheless, I am still learning, but I would love to have the experience that the auctioneer has, simply because he has seen far more fakes coins than myself.

Things to be emphasised: never buy a very valuable coin, unless it is from a dealer of the highest reputation, and knows his stuff in his field of expertise, and if at all possible, examine the piece 'in hand', before making a decision to buy. Keep all of the purchase documentation relating to the particular coin.

As Tom says(Richard)just know your subject and your dealers.

Sorry about jumping in late but I have been traveling lately. Enjoying a bit of vacation - not that I was away from ebay long either.

The art of forgery detection can be mastered at many levels and the suggestions put forth are very good. However, the reliance on tools should never replace the brain. I think, as noted above, that even a test as simple as a magnet can at times lead to a false indication. So never relay on ONLY one form of test. Also never rely on TPG slabs alone. Just in the past week during my travels I spotted three encapsulated counterfeits. That is scary.

The forgers working today operate at many different levels just like the forgery detectors. It is a game. You figure out one sure fire method and next week it is corrected by the vigilant forgers.

So first, expect that anyone anytime can be fooled. Just don't get fooled ALL the time.

Try to check every angle and never defend the coin you are looking at. The coin has to prove it is real.

What I mean is that too many "corroded" 8Rs are accepted as genuine just because some are in fact real. Corrosion covers a multitude of forgers errors. It also "excuses" cast copies. Chops can be used to do the same thing - hide errors. So never describe authenticity because of a post strike feature.

The two keys to begin with are:

1. Know how the genuine coin was made and all the features of such a coin. You need to know it as a friend. Not just whether it was cast or struck but what kind of process was used. A roller press and a screw press produce remarkably different appearances. A collared press produces a different look than either of the preceding with regard to the traces the press leaves behind. Know how the dies were made too and learn to tell the difference. Engraved dies, punched dies and hubbed dies all have different looks. Die wear imparts traces - micro cracks - erosion lines and clashes. Knowing how these features look on genuine and counterfeit coins is essential. What metal was used and how was it processed.

2. Evaluate if what you are seeing in your coin matches what should be there. Learn from every coin you look at. This is your money and your hobby. Don't pass up on the opportunity to learn especially from errors you will make.

The heart of the issue is knowledge and familiarity. My daughter has been a bank teller for years. She is very good at spotting counterfeits and can do it without looking at the bill in many cases. How she did it was familiarity.

I would guess that I never look at fewer than 1000 coins per day. Of course I am retired so I have that luxury of time. Keep looking keep learning.

And if you get stumped or have a question ask someone like me - I will give you a free opinion on any coin if you send clear pictures of both faces and the edge if possible.

Talking about fake slabs here is more with quality photos from Coin forgery ebay group.

http://groups.ebay.com/forum/Coin-F...me/100037396?

http://www.flickr.com/photos/coinforgeryebay/