The silver work on these was done at my desk while watching cartoons. The backs are .925 sterling while the bails, bezels, and marbles are all .999 fine silver. The rocks are from all over the world. I hit every rock and gem show I can find as well as the internet and local resources right here in Moab to keep a constant supply of the most unique and varied stones. The back has my signature, as uninspired as it may be, and the year it was made. I will gladly ship internationally. If you have any questions please feel free to contact me. (My mercury dime is not included.)