Stone of Wisdom

Until 2014 you received experience equivalent to 5000 times your level by handing this stone to Milos (here) or Trimegis (here). As of August 29, 2012, you can only use one stone per year, and only when the Rise of Devovorga event is active (September 01–07). On worlds which were successful on completing the event, players can use this stone up until the server save on September 30th. In 2014, it was replaced by Stone of Insight. Reward of the Rise of Devovorga World Quest, for characters who damaged Devovorga or one of its incarnations.

This stone was extremely valuable right after it was released on September 1, 2010 because there was no limit to how many stones of wisdom you could use at a time. The stone of wisdom was created for the intention of providing players an easy way to recover their lost experience while doing the Rise of Devovorga World Quest. However, due to the abuse of such item from some players, this item was then adjusted by CipSoft in the next update - the stone could be used at any level but only one stone could be used per month. Needless to say, this adjustment to the item drastically dropped its price. As of August 29, 2012, the amount you can trade in decreased to one per year, and only during the event.