I know this must be a pretty rare chip but it just doesn't look right to me. the seller also had a $1.00, a couple $5.00 and a 2 - 3 of these $25.

It almost lookes liek a paper printed inlay on a beat up Nevada Mold.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=290220973743&ssPageName=STRK:MEWA:IT&ih=019

Could this chip been from a recent dig?