I'm pretty sure that the quarters weren't that pure, I don't know. I do know people were melting them down (or at least were suspected of melting them down, I don't know if they actually were), so they changed the composition. My grandfather collected coins and I sort of vaguely remember all of this from him.

I do have a ton of silver dimes and quarters in a drawer though. I should probably just sell them because I was keeping them around as a 'just in case' thing but the value of silver is not exactly shooting up and I really don't care about coin collecting beyond the design of coins in various countries being interesting from an artistic sense.