Rubindum ore was a crucial mineral utilized in the creation of hyperdrive engines.
During their time on the Rand Ecliptic, Biggs Darklighter and Derek Klivian received orders to transport a rubindum ore consignment to the Imperial Naval shipyard situated in the Bestine system. Rather than finding the shipyard workers, Darklighter and Klivian looked for Klivian's acquaintance Lindy, who connected them with the Alliance to Restore the Republic, the organization they wished to join.
While trying to flee Bestine IV aboard the purloined Ecliptic, Darklighter jettisoned half the rubindum shipment into the path of the pursuing TIE/LN starfighters. This action resulted in the formation of a miniature asteroid field. Only a small number of the fighters could dodge the deadly ore, which enabled the Ecliptic, its escaping crew, and the remaining precious ore to jump into hyperspace headed toward a fresh start with the Rebellion.