In my case, the magnet did nothing meaningful to the coin so it passed the first test. While this helps to eliminate lots of easy fakes, it still could be made out of non-magnetic metals or alloys, like zinc, copper, aluminum, and so on. Therefore, I had to do a couple more tests.
Why did they stop making 90% silver coins?
The coins have to work in vending machines and telephones. In the United States, mimicking the look of silver coins was considered important when the minting of 90% silver coins ceased in 1964. The question of acceptability was raised again.
Is it illegal to turn copper foil into gold?
Copper foil could be used instead, but coins are better since they are everyday articles, and there are bound to be requests from the audience to turn copper into ‘gold’. Strictly speaking it is illegal to ’deface coins of the realm’, so the law-abiding teacher might prefer to use foreign coins instead.
