I recently watched a video on how to check a silver ingot with a magnet. On the video they mentioned that you can’t use this to test a coin, because the coin is too small. But what if you had a series of coins? Say 6 or so coins affixed to a stick with blu-tak or similar, or maybe in a frame? Would the coins need to be stacked several deep?
Would what work? You haven’t told us what the method is supposed to be, nor linked to the video so we can see for ourselves.
You can test for conductivity using electromagnetic induction (this is what metal detectors do), and silver would be an easy metal to pick out that way, since it’s the most conductive of all of them. And in fact this can be used for coins: It’s one of the tests vending machines use. So maybe that’s what your video was doing.
Silver exhibits fairly high diamagneticism and the claim is that magnets will slightly stick to diamagnetic materials. That is contrary to the explanation of diagmagnetism that says it repels magnets. So I have no idea how the test is supposed to work, but this video says a neodymium magnet will slide slowly off of a tilted piece of silver like a coin.
I just tested that with a strong rare-earth magnet, and a silver dollar, and it’s true.
But, I’m not sure what that proves. I tried it with a block of aluminum, and the magnet slid much more slowly.
The test in TriPolar’s link looks valid: It’s an application of the induction method I mentioned. The magnet moving across the metal produces changing magnetic fields, which produce induced currents, which produce an induced magnetic field, which acts to slow down the magnet. The better the conductor, the stronger the effect, and as mentioned, silver is the best known conductor at room temperature. Note that conductance depends not only on the material, but also on its dimensions: The block of aluminum works better simply because it’s so thick.
This isn’t a very precise method, though, and I’m not convinced it could be used to reliably distinguish between silver and (say) copper, which has nearly as good a conductivity.
So a magnet is useful for screening, you can eliminate low and non-conductive materials, and iron bearing materials, but you aren’t verifying silver content. I’ll stick to the tried and true method for testing silver, form it into a bullet and see if kills a werewolf.
Where are you getting your werewolves these days? Most pet stores won’t sell them to you anymore if they know you’re just going to shoot them with silver bullets.
It was a while ago and I don’t recall exactly which video it was.