Here's a convenient way of how to tell if you have real silver coins/rounds.

Carefully balance the coin flat on the tip of one finger, then use something like a pen to gently strike the edge of the coin. You should hear a melodious ringing sound which should gradually fade away. If the material is copper etc you will get a higher pitched 'tinny' sound which doesn't last as long.

Obviously it helps to have something to compare the sounds with.

I tried this method with two Kennedy half-dollar coins. One was a 1964 with 90% silver content, and the other was a 1980 with 0% silver content. Both coins looks the same (except for the metal colour) but there was a very noticeable difference in the ringing sound produced.

The method isn't foolproof, but it doesn't cost anything and is easy to do.

Please view my other guide for information on the fake silver round I bought on ebay.