The coin is platinum - .9995 platinum 1/4oz. Face value is $25. When I got it, I was told to hold onto it because it's supposed to go up in value, but I'm not really sure how all that works. My question has to do with the eagle on the back and the date on the front. A lot of the websites I've looked at show images of all the platinum bullion American Eagle coins from 1997 to present. But the images don't match. Here http://platinumeagleguide.com/1997-platinum-eagle/ is the 1997 coin and that's the one that matches mind, while the 1998 coin, here: http://platinumeagleguide.com/1998-platinum-eagle/ doesn't. So I'm kind of confused. Do the date on the coin not mean the date it was minted? Why does mine have the image from a different year, but the same face value?
Your coin is indeed a 1998. The coin you linked is a proof, your coin is not. They had different reverses.
