I've done diamonds in Arkansas, found a little one once. Garnets in Idaho did pretty well, opals in chihuahua mx, tourmaline, topaz, beryl, in NM and CO, agates and jasper all over the southwest, and lots of other gems around the country. Haven't done it in years, but I wanted to be a jeweler when I was a teenager, and my dad has a geology degree, so we did lots of digging around. We did a few days of metal detector mining with a retired miner in NM, who had a played out claim he had bought years ago. He did cuts into the ancient river beds with a dozer, and dug nice nuggets out of the walls of the cut got a few little ones. He had also found a doubloon on a hilltop in the area years before. I'd love to know who dropped that.