Thanks - I wasn't sure if the toning was only a result of the material in the slab or combination of material and heat or humidity.
I know it is an old thread, but an interesting one. I am not sure how many believed Lehigh when he posted this, but maybe this will change their minds. Found this coin on eBay (from http://cgi.ebay.com/1998-1-1OZ-Silv...tem&pt=LH_DefaultDomain_0&hash=item588860b2a5). Anyone think it looks familiar?