Moon Stone

Moon Stone (あんこくせき) is a Key Item in Chrono Trigger. It is obtained by beating the Son of the Sun in Sun Shrine during the Future.

Story
The Sun Stone was used as the primary energy source by the Kingdom of Zeal before the advent of Lavos and the Mammon Machine. When it runs out of energy, it becomes a Moon Stone. It can be turned back into the Sun Stone, but it must be left in the sun for a period of over 65 million years.

It is briefly stolen in 1000 A.D. by an explorer, who delivers it to the Porre Mayor. Through changes in time, the mayor, originally greedy, became a jovial man who yields the stone to the party without a hitch.