Essurtanium was a rare substance. It was believed to have unusual properties, including potentially being slightly Force-reactive. During the High Republic Era, some miners on the southern hemisphere of the Outer Rim Territories planet Elphrona believed they had found some essurtanium, and Jedi Indeera Stokes, stationed at the Elphrona Outpost, intended to visit the miners and collect a sample of their find for study before the Jedi of the outpost were called to deal with a Nihil raid.
Essurtanium was first mentioned in the 2021 novel The High Republic: Light of the Jedi.
- Star Wars: The High Republic: Chronicles of the Jedi