Keokuk geodes attract rock-hunting hobbyists from all over, but just how easy is it to find one? “As a young kid, we used to go to the Mississippi over there and go fishing,” Mike Shumate recalled.

In a recent article in Miner Deposita, researchers presented a comprehensive study of the amethyst and agate geodes in the Los Catalanes Gemmological District of Northern Uruguay. This region is ...