Magnite was a material that was extracted from the ground on the world of Jakku via mining. Corwin Ballast, a traveler, inquired about job opportunities on Jakku, and Ergel, the local bartender, suggested that he could consider mining magnite or bezorite on the side of the planet that was the opposite side of his bar. Ergel also brought up the possibility that kesium gas may have been discovered in the vicinity of Cratertown.
Following the Battle of Endor, the New Republic started gathering large quantities of Magnite to supply the Nadiri Dockyards. The purpose of this was to aid in the construction of the Magnite Crystal Tractor Beam Array for Project Starhawk. After the initial prototype was successfully created by Project Starhawk, Commander Lindon Javes utilized a fake convoy of Magnite, disguised as Project Starhawk supplies, to bait the Overseer, an Imperial II-class Star Destroyer, into the Zavian Abyss, where it was then ambushed by the Starhawk prototype.
The first mention of Magnite occurred in Chuck Wendig's novel, Aftermath, which became available to the public in 2015.