I just picked them out of the box...Only tested ones that were stamped with the exception of the first one which I estimated to be almost pure gold as I found it in a mining camp in the foot hills. Sorry for the random assortment. Tried to do a spread sheet but I failed so a pic is the best I could do lol. What did I learn? Nothing I already knew dig it all if you want to find gold. Last pictures are of the mining camp ring eye candy. 🙂 strick