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Easy ways to tell if an old coin is authentic/fake?

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Cuthwellis
Joined: 26-Jul-2018
Posts: 258
Hello! I have a question I've wanted to ask.

I have bought quite a few old coins on eBay, from Ancient Rome to the eras of Henry II or George III or Louis XIV, but often I hardly can be sure if the coin is real or not as I'm still not too familiar with them (I prefer worn but identifiable ones for that reason).

For example, some centuries-old copper coins may look glossy and rather smooth, and I can't tell if they are supposed to. To see if they are really old, the only easy method I can think of is softly scrubbing them on tissue paper and see if they leave marks of rust or dirt. Do you think this is a good way? I think it pretty much confirms the coin's age but could it be just paint or whatever the forgerer used to make/colour it coming off?
Twopence a week, and jam every other day!
CassTaylor
Joined: 30-May-2014
Posts: 6487
Quote: "Cuthwellis" To see if they are really old, the only easy method I can think of is softly scrubbing them on tissue paper and see if they leave marks of rust or dirt. Do you think this is a good way?
​To critique your method, I don't think it's a good way of going about it.

Wouldn't a dirty fake made yesterday have the same effect?
Une Franglaise; ♪ je brosse ma chevelure ♫
Cuthwellis
Joined: 26-Jul-2018
Posts: 258
Oh...of course. I have no counter argument for that. Can't believe I didn't think of it at all!
Twopence a week, and jam every other day!
Idolenz
Joined: 13-Jul-2013
Posts: 1977
There is no easy way, only when fakes are very bad and even those fool many people, at least the ones blindly buying without a second look and thought.
The only way is to get familiar with the coins (literature, threads about forgeries, photos, real specimens etc.) but this is a long process ... there is no shortcut.

And yeah ... no rubbing ;)
              
CassTaylor
Joined: 30-May-2014
Posts: 6487
No worries, we all make mistakes. :)

What you say about liking "worn but identifiable" coins I actually think works (somewhat) well. Modern fakes are almost never deliberately made in low grades, and especially for silver I don't mind lower grade specimens for my type collection, so it all checks out. They tend to be cheaper too, so that's a bonus for me.
Une Franglaise; ♪ je brosse ma chevelure ♫
pnightingale
Joined: 27-Jul-2011
Posts: 5101
The easiest way is to weigh it with a set of inexpensive digital scales and measure it with calipers. These ought to be the first purchase for any collector passing beyond the novice stage. You can buy them locally for as little as $20, even cheaper online.

It's more useful for modern machine made coins, especially larger silver types but apart from helping you detect forgeries, both recent and contemporary, you will need them to identify your more obscure coins.
Non illegitimis carborundum est.  Excellent advice for all coins.
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Cuthwellis
Joined: 26-Jul-2018
Posts: 258
Hmmm. I see! I think weighing them is reasonable – maybe unless the coin is very old and badly chipped, like a lot of Roman ones are? – and since I do tend to buy worn coins if they are old, I may just be worrying a little too much. The history is what I like about old coins, after all!
Twopence a week, and jam every other day!
Topic moved to "Numismatic questions" (ZacUK, 9-Sep-2018, 09:19AM)
loruca
Joined: 11-Apr-2015
Posts: 646
Quote: "Idolenz"​There is no easy way, only when fakes are very bad and even those fool many people, at least the ones blindly buying without a second look and thought.
​The only way is to get familiar with the coins (literature, threads about forgeries, photos, real specimens etc.) but this is a long process ... there is no shortcut.

​And yeah ... no rubbing ;)
​Actually, I disagree, there IS a shortcut.
Post them here!
We like seeing coins, and we're rarely wrong.
(That being said, and putting aside all humour, Idolenz is right. It is a complicated time consuming process to actually learn, but it is rewarding.)
Note: you could also buy from a reputable dealer. That tends to cover your bases too.
I collect anything: If it's Italian or Italian states i collect it even more!
Kipsley
Joined: 3-Feb-2018
Posts: 152
There are some websites dedicated towards identifying fake coins. I once came across a 1930 KGV penny on eBay that was given as being genuine (at least nowhere in the description did it say it was a replica). I looked it up and sure enough there is a site dedicated to spotting these "fakes". It was very helpful and within an hour or two I was able to identify the coin in question as being a fake, but a real good one.

Maybe there are some sites that can help you with the identification of fake or replica Roman coins?
Collector of Third Reich coins (1933 - 1946), and Australian coins.
Not swapping at this time.
halfdisme
Joined: 6-Oct-2017
Posts: 614
There is another problem in trying to separate genuine ancients from contemporary counterfeits--and some locations/tribes simply imitated their neighbors, rather than creative their own designs!

(As I recall, the Romans once determined that a high percentage of the coins in circulation were fakes. Because of the shortage of coins available, they counterstamped some to permit them to stay in circulation.

An eBayer wrote to complain about an ancient she had bought from me several years ago. While washing it in her sink, someone set something down on it, and the coin split into quarters. She thought that proved it was a fake, which sounded odd to me.

I asked Harlan Berk (Chicago dealer in ancients) about it. He said she had just proved that it was genuine. It takes many years for the metal to crystallize in a manner that would cause it to shatter like that!
CassTaylor
Joined: 30-May-2014
Posts: 6487
Quote: "halfdisme"
​I asked Harlan Berk (Chicago dealer in ancients) about it. He said she had just proved that it was genuine. It takes many years for the metal to crystallize in a manner that would cause it to shatter like that!
​About that; do some metals crystallise and shatter like that sooner?

I had a 1942 Tunisian 10 centimes in zinc from WWII; it literally broke into two as soon as I had taken it out of it's 2x2. I've also seen (not metal, I know!) Manchukuo red fibre coins broken into two as well.
Une Franglaise; ♪ je brosse ma chevelure ♫
loruca
Joined: 11-Apr-2015
Posts: 646
Quote: "halfdisme"​There is another problem in trying to separate genuine ancients from contemporary counterfeits--and some locations/tribes simply imitated their neighbors, rather than creative their own designs!

​(As I recall, the Romans once determined that a high percentage of the coins in circulation were fakes. Because of the shortage of coins available, they counterstamped some to permit them to stay in circulation.

​An eBayer wrote to complain about an ancient she had bought from me several years ago. While washing it in her sink, someone set something down on it, and the coin split into quarters. She thought that proved it was a fake, which sounded odd to me.

​I asked Harlan Berk (Chicago dealer in ancients) about it. He said she had just proved that it was genuine. It takes many years for the metal to crystallize in a manner that would cause it to shatter like that!
I had that happen to a beautiful Roman denarius which I was using as a pocket piece due to some horrible over-dipped surfaces. I get up from lunch, and I have silver granules in my. pocket...​
I collect anything: If it's Italian or Italian states i collect it even more!
halfdisme
Joined: 6-Oct-2017
Posts: 614
Quote: "CassTaylor"
Quote: "halfdisme"​​
​​I asked Harlan Berk (Chicago dealer in ancients) about it. He said she had just proved that it was genuine. It takes many years for the metal to crystallize in a manner that would cause it to shatter like that!
​​About that; do some metals crystallise and shatter like that sooner?

​I had a 1942 Tunisian 10 centimes in zinc from WWII; it literally broke into two as soon as I had taken it out of it's 2x2. I've also seen (not metal, I know!) Manchukuo red fibre coins broken into two as well.
​I do not know.

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