Posted 05/06/2007 05:05 am
For foreign coins, it's not an easy question to answer, for several reasons.
The fineness of the silver used in a coin could be anywhere from .999 fine to .250 fine or even less - some Mexican and German States coins are .100 fine! Normally, once you get below 50% silver, a coin doesn't look "silvery" anymore. The fineness of the silver, and the thickness of the coin, can both throw out the accuracy of Metalman's "ring test".
Dealers who handle lots of foreign coins and desire to separate out the silvers from the silvery base-metals learn by eye the subtle difference in colour and appearance. And, of course, they always have the books to fall back on if they're unsure.
There are a few simple tests you can make. Try a magnet; if it sticks, it's steel or pure nickel, not silver. Not sticking to a magnet isn't proof of silver, though; it might be cupronickel or some other alloy.
Some people claim to be able to smell silver. Try it with a handful of coins, and see if you can tell the difference. I can't say I've noticed myself. Not sure it'll work well on an object as small as a coin, but if you have this gift, use it.
Once you've done the easy things, your options are fairly limited, I'm afraid. You can:
- play Archimedes and measure the density/specific gravity.
- try chemical testing. Silver has different chemistry than copper, nickel, etc.. Some places like this sell acid "silver testing kits" which give a rough idea of the silver concentration in the alloy. Of course, chemical testing is "destructive" and will damage the coin, as far as a collector is concerned.
- There are non-destructive, accurate tests you can make, but you need some seriously heavy gear - like an X-ray flourescence spectrophotometer, for instance.
The fineness of the silver used in a coin could be anywhere from .999 fine to .250 fine or even less - some Mexican and German States coins are .100 fine! Normally, once you get below 50% silver, a coin doesn't look "silvery" anymore. The fineness of the silver, and the thickness of the coin, can both throw out the accuracy of Metalman's "ring test".
Dealers who handle lots of foreign coins and desire to separate out the silvers from the silvery base-metals learn by eye the subtle difference in colour and appearance. And, of course, they always have the books to fall back on if they're unsure.
There are a few simple tests you can make. Try a magnet; if it sticks, it's steel or pure nickel, not silver. Not sticking to a magnet isn't proof of silver, though; it might be cupronickel or some other alloy.
Some people claim to be able to smell silver. Try it with a handful of coins, and see if you can tell the difference. I can't say I've noticed myself. Not sure it'll work well on an object as small as a coin, but if you have this gift, use it.
Once you've done the easy things, your options are fairly limited, I'm afraid. You can:
- play Archimedes and measure the density/specific gravity.
- try chemical testing. Silver has different chemistry than copper, nickel, etc.. Some places like this sell acid "silver testing kits" which give a rough idea of the silver concentration in the alloy. Of course, chemical testing is "destructive" and will damage the coin, as far as a collector is concerned.
- There are non-destructive, accurate tests you can make, but you need some seriously heavy gear - like an X-ray flourescence spectrophotometer, for instance.
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
when he said " learn by eye the subtle difference in colour and appearance." of silver. Especially in the more common coins that you would be coming upon in your normal way of life.
