Sky Gold, also known as Blue Aurum (ブルーオーラム Burū Ōramu), is a valuable source of fuel found on the planets, Earth and Jung.
Sky Gold is a rare material seen in Jaco the Galactic Patrolman. It also exists outside of Earth as it is the fuel for Jaco's spaceship and is known as Blue Aurum. It is used to power all sorts of machines.
The Macareni Siblings attempted to steal a trainload of Blue Aurum but was stopped by the Galactic Patrol. Upon escaping from the prison they return to Jung and successfully steal it then head to Earth where it is known as Sky Gold to steal more.