Quantumite is a powerful naturally occurring crystal found on Halley's Comet. While it is incredibly powerful it is very unstable, as crystals are wont to be.
Challenge of the GoBots cartoon
A sample of quantumite was found on Halley's Comet by a joint Guardian/UNECOM flight, and was such an exciting discovery the team cut short their exploration so Professor Von Joy could immediately patch it into the new Star Fortress' power supply. It immediately boosted the station's shields to such levels that the Renegades, preparing to assault the station in Thruster, were unable to get anywhere near the Star Fortress. Alas, the quantumite predictably enflamed Cy-Kill's greed, and he promptly took over a second flight to the comet to allow his troops to sneak past in a UNECOM ship that headed to the comet to collect more of the crystal. Taking the Guardians by surprise, Cy-Kill and his troops were able to get to the quantumite and disconnect it. However just as they reached Thruster he was surprised by A.J and Nick and dropped the quantumite, which immediately began to react with the floor. There was time for the Renegades, Guardians and UNECOM to evacuate the Star Fortress before it was totally destroyed by the quantumite. The Secret of Halley's Comet