The Aurora Stone was possibly the largest crystal in existence in a refined state; at one time, it was placed in beacon tower on Terra Atmosia. It was stolen by Master Cyclonis to power her Storm Engine though later destroyed by Aerrow to save Atmos.
The remaining Red Eagles of Terra Atmosia later managed to infiltrate Cyclonia and retrieve the remaining pieces of the Aurora Stone. They then placed them on an Altar within the Beacon Tower. While the stone was in its altar the surrounding weather was sunny with slight white clouds. When the stone was taken by Cyclonia, the skies became dark and stormy, showing that the stone offers some form of protection to the citizens of Atmosia.