What are Dilithium Crystals

Finally, the Star Trek writers added one more crucial component to the matter-antimatter drive. I refer to the famous dilithium crystals (coincidentally invented by the Star Trek writers long before the Fer-milab engineers decided upon a lithium target in their Antiproton Source). ...What do these remarkable figments of the Star Trek writers' imaginations do? These crystals (known also by their longer formula 26 dilithium 21 diallosilicate 1:9:1 heptoferranide) can regulate the matter-antima...