Irilumium-67

Irilumium-67 is a radioactive isotope of the element irilumium (Iu). It is predominantly found in Nilur near the Gretican-controlled Hayek Pool, but there are smaller amounts in the Rearmest Greatlands of Thalume. There is no known amount of 67Iu in Serata. Its potential for clean energy is the basis of gravium trade between the All-Tribe, who seek to skip a dirty industrial age, and the Greticans, the only space-faring people in need of gravium.

67Iu is the base component for the Gretican nuclear warhead used during the Dawn War and remains a vital part of the Niluran economy. The Greticans have developed nuclear energy in almost every capacity of life, including CHORE and space flight, making transportation far less expensive than with traditional rocket fuel.