These old 10 dollar pieces are really pure gold. They also have more rounded edges to the serration around the rim so they don't need to be filed or modified in anyway to use as a guitar pick. They are also softer and wear out faster than later 10 dollar gold pieces. They lack the top end luster of debased gold currency when used with a humbucker, but they feel better in your hand and are just a joy to play 1 line lead parts with. Please see my other review of vintage USA gold pieces as picks for more info.