I sell lots of silver and only one buyer ever used a magnet to check a kilo bar. It didn't seem very conclusive to me. Nobody (in the last 10 years at least) would use iron or something magnetic when making a fake.
You should try sliding a rare earth magnet off a silver bar, its not about sticking to the bar, it sabout resistantce to any sort of movement
The "slow sliding" effect is not about silver being non-magnetic, or because of its position in the periodic table (well, only very indirectly, because it's #47), it's because silver is the best electrical conductor. When a magnet moves near a conductor, small eddy currents are induced inside the conductor, which in turn create magnetic fields of their own. These new fields interact with the magnet's in a way that tends to slow its movement. Other metals will do this also, especially copper, but the effect is strongest in silver because being the best conductor, the eddy currents are stronger. The difference is small though, so as a test for silver, I have my doubts. If you move a magnet quickly near some silver, you can feel the resistance. Trouble is, it feels almost the same with aluminium...
Just get a scale and a tool to measure the specs of the coin and compare them to the actual weight and thickness of the coins rim. The magnet and ice test can also work as well. As stated , buy from reputiable dealers which will almost minimize getting a fake.
