Durelium: a substance that smugglers could make money from. In Smuggler's Guide by Maz Kanata, the pirate advocate Platt Okeefe suggested it as a worthwhile cargo for generating revenue, alongside meleenium and hyperbarides.
The reference book Star Wars: Smuggler's Guide by Daniel Wallace from 2018 brought druelium into Star Wars canon. It first appeared in the Star Wars Legends role-playing game supplement Pirates & Privateers from 1997.