That is the first incident I know of where someone found one of my designs while metal detecting. Note that I did the original graphic design for this item, but I had no involvement with the sculpting, engraving, minting, marketing, or distribution of it. The first issue was 2004 and the pieces were marketed as a "government-issue silver dollar" from the Commonwealth of the Northern Mariana Islands (CNMI). But CNMI is a US protectorate and can not issue its own money (they use US Dollars). As such, the first issue was technically illegal. Starting in 2005, the marketer of this item (National Collectors Mint) switched to a Cook Islands (CI) issue. CI will let just about anybody make a coin using their authority, so long as you pay the royalties. The CI issues were made each year from 2005 to 2009. The later the year, the scarcer they are. The CI pieces from 2005-2008 are listed in the Krause World Coins Catalog as KM# 470. The 2009 issue is unlisted in that catalog. Most were only silver plated. But some were made in solid 999 silver and the edge marking will state "1 TROY OZ..999 FINE SILVER". Here is more info and pictures (scroll down a little to the Freedom Tower section): http://www.moonlightmint.com/other.htm .