when you complete grandpa's shrine and get the statue of perfection, there's a glitch that allows you to get more than one!
if you happen to "lose" the statue, the shrine will give you another, and the game classifies any block that's broken/dropped and not picked back up missing. so if you keep leaving them, there's no real limit to how many you can get :)
genuinely the easiest and fastest way to get iridium ore in the game!