Tiberium

Tiberium is a volatile element used in the powering of several common types of power systems. Matthew Donahugh lived on board the Peloponnesus, a tiberium freighter owned by his family, for most of his childhood and teenage years.

Due to unprocessed tiberium's volatile nature and its reaction to high warp speeds, it cannot be transported at speeds over warp 5. Trips transporting the element could take months at a time.