Coridan is the collective name of a group of inhabited worlds in the Coridan system, whose admission to the United Federation of Planets was debated and ultimately approved during the Babel Conference of 2267. The Coridan worlds are notable for possessing an abundance of dilithium, a mineral indispensable to the operation of warp-capable vessels. As early as the 22nd century, Coridan's central planet was the prosperous home of some three billion humanoids. Within a century's time, that population had been greatly reduced, rendering the Coridan planets vulnerable to illegal dilithium mining operations, which were curtailed considerably by admission to the Federation.