Long story short, Crinium. It is used in conjunction with iridium to create tier IV tech, along with a player modification machine. Crinium would spawn in meteor craters, which are quite rare, and in small quantities.
The Player Modification Machine would have many functions, mostly related to boosting the base stats of the player, such as health regeneration rate, natural armor, jump height, speed, damage, mining speed, and getting more food out of things/getting rid of debuffs at a cost of hunger.
Totally not a reference to a recently written story by Al.