Tricellite
From Star Trek : Freedom's Wiki
Tricellite was a durable, long-lasting mineral used as a substitute for zelebium in the guidance systems of Erstwhile-type freighters. Some star systems, for instance Omega Sagitta, lacked this mineral.
In 2365, the guidance system aboard the Erstwhile, commanded by Captain Thadiun Okona, was repaired with tricellite. (TNG: "The Outrageous Okona")
