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testing with magenets for authentic age (iron mainly)


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was testing my chinese 3 cash from the northen sung (1086-1100) with a magnetic screwdriver (had to repair comp) and tested it against some more recent iron pieces (german notsgeld etc) and noticed that the german stuff stuck to the magnet, however the cash coin had very little pull whatsover (it was slight but hardly any movement towards it) and i know that magnetism fades over time, so is this a good test to do for authentic age?

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I'm guessing theres way too much variability with the methods, subject, and instrument to make that a "good test". Great thinking though. Wouldn't it be cool to have a spectrum of magnets you pass over each coin at a set height. When the coin gets attracted, then the scale tells you the age!

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well i got a rusty 1918 german notsgeld piece and it stuck.


Yes, but it was still be mostly steel under the surface.


The cash coin is likely throughly rusted. The other issue is the amount of alloy present (zinc et al.), and how that might affect the magnetic properties.

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I know iron is magnetic, but is iron oxide magnetic?

Oddly enough almost anything could be made to be magnetic. And yes, even Oxides of metals stay magnetic if the original material was magnitized.

And example of this is AlNiCo, which is really a powerful magnet and yet contains no Iron at all.

Magnitism can spread from one substance to another also, so using a magnet on a coin is not real smart. Magnetically inducing such a polarity could create more rapid Oxidationing of your coins.

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