Hi! I have a miniature of St. Gauden's first $20 14 karat gold piece along with a certificate of authenticity. I needed a magnifying glass to see the wording. It says Liberty MCMVII and the other side says United States of America Twenty Dollars. I found something on youtube that claims the full size coin is very valuable but could not see anything about the miniatures from 1907. Does anyone have any idea?
The diameter of the MCMVII St. Gaudens is 34 millmeters and a weight of 33.4 grams. If yours is less than that, it most likely is a 14k gold plate copy and not worth anything. Yes, the full size St. Gaudens is quite valuable depending on the variety and can start around $2200 in G, and go as high as $200,000+ in PR.
Certificate of Authenticity The World's First Miniature Solid 14 Karat Gold $20 GOLD PIECE This is to certify that the $20 gold piece is solid 14 kt. gold - an authentic miniature of St. Gauden's first $20.00 gold piece minted by the Historic Providence Mint in accordance with the guidelines established by the United States Secret Service Division of the Department of Treasury. Serial Number * 014305 Joseph W. England Managing Director The Historic Providence Mint HC-116
That being the case, then it's a simple matter of doing the math. Weigh the piece. We'll presume you get a weight in grams. Multiply the grams by .0321507466 (There are .0321507466 Troy Oz in a gram) for a total Troy ounce Weight. Multiply that weight by .58333 (14k gold is 14/24 or .58333 "pure" gold) This will give you the troy ounce weight of "pure" gold in your coin. Multiply that by whatever the current bid price for gold is (which you can find at kitco.com, monex.com, or a dozen other places) and you'll have the melt value of your coin.
The COA should also have the weight of the miniature repo St G. listed somewhere. According to Wikipedia 14K gold is somewhere around 58% pure gold. here's an auction sale of one of them but you need a subscription to see the sell price http://www.worthpoint.com/worthopedia/solid-14k-gold-miniature-gold-coin-116041681 I assume it's worth gold melt prices.
Welcome to CoinTalk. Enjoy your time here. The original coin is very valuable, yes. Copies of any kind are not. Your mini gold coin is worth no more than its gold content, as others have said. But ebay shoppers are surprisingly unpredictable. You might get a few dollars more. Lance.