Beryllium is a resource that is the heart of Quantum Flux Drive technology, mostly in the form of Beryllium Spheres.
Beryllium is a unique metal that seems to naturally form into spheres, its natural unrefined state seems to be the most useful. The bivalent nature of beryllium and its transparency to ionizing radiation makes it an ideal quantum resonance substrate.
Before quantum flux technology became a reality the great physicist Zachary Clampett spent years bombarding ingots of pure beryllium metal with high-energy neutron beams. The results were dissapointing, ironically it was not until he used a sphere of raw, unrefined beryllium that he was able to build a working quantum flux drive.
Sadly it took a decade until spaceship builders started using Clampett's technology, because they were too heavily invested in engines powered by imported rocket fuel. Now unfortunately its usage has made beryllium extremely valuable, and NSEA vessels in certain parts of the galaxy have been forced to post armed guards in their generator rooms to avoid being victimized by Beryllium Pirates.
In the real world it seems that Beryllium is much the same as it is within the fictional galaxy question universe. The Thermians have used it in an identical manner to the original TV series.