I purposely bought a fake trade dollar just to see what it looked like. Some sort of nonmagnetic pot metal which was a little on the light side. The strike was pretty good although the die obviously came from a worn coin. The luster was terrible, didn’t look right and obviously didn’t feel right. But it would be pretty scary if they stamped the coin from real silver and “forgot” to mark it as replica on the back.
I just tested one of the coins with pure nitric acid and it turned bright green immediately. Lots of copper in them.