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 Replies: 12 / Views: 1,660 |
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New Member
Canada
46 Posts |
If I have a silver-colored coin, that does not stick to a earth magnet, is that coin automatically assumed to be composed of silver?
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Pillar of the Community
United States
797 Posts |
Unfortunately no, it can also be Pewter, which also is no ferrous
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Pillar of the Community
United States
4897 Posts |
Take your rare earth magnet and do small circles over the proposed silver object. If it has silver you will create eddy currents (changing the magnetic field of the conductor causing the creation of a magnetic field). Silver is diamagnetic (creates a magnetic field in opposition of an external magnetic field). You should feel a "push" against each field if the object contains silver. Caveat: this is all off the top of my head so may be wrong?  |
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Pillar of the Community
 Canada
9864 Posts |
What's the coin?
"Dipping" is not considered cleaning...
-from PCGS website
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New Member
 Canada
46 Posts |
What about cupronickel, that isn't magnetic is it?
@DBM, just searching through a world coin lot, and most of these coins are dateless.
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Pillar of the Community
Canada
1005 Posts |
Cupro-nickel coins will not stick to a magnet.
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Pillar of the Community
United States
1234 Posts |
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Moderator
 Australia
16831 Posts |
Unfortunately, technology has not yet reached the point where you can buy a cheap "coin tricorder" you can wave in front of a coin and it reliably tells you whether it's silver or not. You can buy (or rent) a portable XRF device which will do exactly that, but they're not cheap and only worthwhile if you're sorting an awful lot of coins or other scrap metal. All other tests for silver (such as specific gravity, the eddy current braking test or the tissue test) and any general rules-of-thumb about dates work for some coins and countries, but not for others. From what I've seen posted on the forums, even jeweller's "silver test kits" can give false positives and false negatives in inexperienced hands. The only thing you can do to be sure to catch all the silver is the hard slog: sort the coins out by country, then use a reference list like the Krause coin catalogue or the list of silver coins on CurrencyDebasement to go through each country, coin by coin. Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Valued Member
United States
337 Posts |
I really cannot see how the eddy test would identify silver. The metallic bond allows electrons to respond to a changing magnetic field in any good conductor, and I really do not think you could circle a magnet fast enough to detect an eddy only if you have silver. Yes, an eddy electric current causes a magnetic field, but can you detect it in the presence of the magnet.
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Bedrock of the Community
United States
20753 Posts |
What type of coin?  Are you sure your magnet is working? Might be a faulty magnet.  Have you tried a Silver Magnet?  You could try the Torch method. Using a high temperature torch, try melting it. If it melts easily, might be Silver, Lead, Radium, Tin, etc. By silver colored, that could really mean anything Silvery in color. Just to vague to know exactly what it could be. Don't forget Zinc too looks like Silver. Now here to is an interesting fact. There are Magnets made of completely Iron free materials. |
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Pillar of the Community
Canada
1005 Posts |
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New Member
Canada
46 Posts |
I only have a iPhone camera, and that's no good for pictures :( I'll be investing is a t5i soon though.
I just meant this as a generic question however.
Like other than silver, were there other other silver-colored coins that are not magnetic as well.
And I got my answer, seems like there is a bunch of them.
Looks like I'm going to have to go through each coin individually like Sap suggested.
Thanks for the help everyone.
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Pillar of the Community
United States
648 Posts |
Quote:
I really cannot see how the eddy test would identify silver. In our TFD tm testers, precision/repeatable trials are made on test coins. Once you know what a silver or copper coin test result is. You also know what it is not, such as brass, bronze,tin,zinc So maybe you could say, we don't identify silver, we ID fakes.  Quote:
Yes, an eddy electric current causes a magnetic field, but can you detect it in the presence of the magnet. Yes, the magnetic field is of a like polarity and slows the magnet down, if it is very close to surface of coin. (Classic magnetic test) aka slide test. Quote:All other tests for silver (such as specific gravity, the eddy current braking test or the tissue test) and any general rules-of-thumb about dates work for some coins and countries, but not for others. well said. |
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Replies: 12 / Views: 1,660 |
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Posted 02/11/2014 2:41 pm
