Draconite ore

An incredibly rare mineral that forms as discoid crystals, aglow with a faint, pale grayish-purple light, Draconite is prized for its qualities of storing and "distilling" energies of the "Aether". When processed, its energy yield is such that it can power a Muchausen drive's lightspeed capabilities. However, Draconite crystals are supremely picky about where they form, and the substance itself is a non-renewable resource. They also appear to easily radiate their energy under certain conditions - i.e., being directly exposed to sea water for prolonged periods of time - And such circumstances cause them to become, for all intents and purposes, utterly useless.

Trivia

 * Aisha Clanclan has said that Draconite is practically the most valuable raw mineral in the Universe.