for iridium ore and the best geodes you wanna go skull dungeon, otherwise in the mines as low as possible so you get to the end and can enter the skull dungeon.... you see where i am going with this... SKULL DUNGEON
You have unlimited Iridium in the third year, but Skull dungeon is a good place to look for more, the lower you go, the more Iridum you can find. I also do 110-120 runs since I found a lot of geodude down there, usually 2 at the same time after smashing rocks.
