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 Replies: 8 / Views: 2,391 |
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New Member
Canada
4 Posts |
You are experienced people, please tell me how, except for scanning a coin, to find out its meanness and age? I only know how you can determine the dishonesty of a coin using the metal analysis method? Are there any other ways?
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Moderator
 United States
187950 Posts |
 to the Community! Your reply was split into its own topic for the proper attention.  |
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Pillar of the Community
United States
1120 Posts |
You can tell the age of a coin by first identifying it. Then you can put an exact or round about date on the mintage.
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Pillar of the Community
United States
3343 Posts |
I was rereading this today. A great discussion of the counterfeiting of ancient Greek coins. https://fsu.digital.flvc.org/island...eam/PDF/viewThe primary methods for detecting counterfeits in ancient times were the touchstone and the coin's weight (especially for tetradrachms, where low weight could be felt in the hand). There was also the trial by fire, which involved putting a coin on a red hot shovel. If it glowed white it was pure silver to the core, if it didn't it was counterfeit. Unfortunately this sometimes destroyed the coin. But in a transaction involving a lot of coins that didn't matter. The author spends some time discussing the reasons for ancient counterfeiting vs modern forgeries. In the case of ancients, the intent was just to get a coin into circulation no matter how briefly, and almost always involved plating base metals with gold or silver. "Two minutes ago I would have sold my chances for a tired dime." Fred Astaire
Edited by thq
03/11/2021 10:14 pm
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New Member
 Canada
4 Posts |
Due to the nature of my job, I have my own portable XRF scanner and therefore I sometimes use it for my needs. I use a handheld metal scanner to find crafts. I do not argue, my method only shows whether a coin is made of the desired metal or not. I also compare the weight of the coins. Sometimes I ask a friend to help me determine the age of a coin. If anyone is interested, he works https://elvatech.com/applications/pmi/ at Elvatech and can help me determine the age of the coin, if, of course, I am sure that it is genuine. Edited by AlexCaffe
03/12/2021 04:13 am
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Bedrock of the Community
Australia
21786 Posts |
Hand held XRF scanner good for accurate analysis of the metal composition in the surface layer only, up to 5 microns deep. Does not reveal anything about the metal composition below the surface.
Very useful for metal analysis of ancient coins. The ancients could not refine much above about 98% purity, and it is the presence of the mismash of trace elements, which are absent in modern discreet coinage alloys, from which a fake ancient coin may be made.
Other tests that can be applied to help establish the authenticity of a coin:
1. weight
2. diameter
3. density
4. ping tone test
5. visual comparison with known genuine examples looking for differences in design details.
6. check against data bases for known fake coins
7. provenance
8. test with a magnet
9. ultrasound test looking for anomalies of core VS surface
10. deep X-Ray testing (different to XRF)
11. destructive chemical analysis - (used to build a data base for analysis of ancient coinage alloys).
12. close examination for alteration of original details such as fake mint marks on genuine coins.
13. Artificial or unnatural accelerated toning.
The first eight abovementioned tests have zero cost, and are easily performed by a coin collector with simple equipment.
Edited by sel_69l
03/12/2021 05:29 am
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Pillar of the Community
Canada
5239 Posts |
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New Member
Canada
4 Posts |
@sel Thank you for this information. Now I know better how to distinguish a genuine coin from a craft
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Pillar of the Community
United States
3343 Posts |
Genuine ancient counterfeits (aka fourrees) are as valuable as the coins they imitate. This tetradrachm is underweight and has been cut (on the owl) to show the base metal core: https://www.vcoins.com/en/stores/bi...Default.aspxThe plating on these coins is generally foil and thicker than modern electroplating. It cracks and flakes off. "Two minutes ago I would have sold my chances for a tired dime." Fred Astaire
Edited by thq
03/12/2021 11:51 am
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Replies: 8 / Views: 2,391 |
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Posted 03/11/2021 9:00 pm
