An item used to help navigate through gateways, and open keystone chests and keystone doors. Set a combination for the keystone by shift right-clicking on it, then place colored runes in your desired combination (the order is clockwise with the top center rune first) and click "remember" after naming the combination to save it. To forget the combination which has been put into the keystone, click forget when you have shift-clicked the keystone. You can toggle between saved combinations if the proper colors of runes are in the keystone by clicking the arrows on either side of the GUI or by clicking on the combination from the list of saved combinations. Remember, only the currently selected combination will have any effect on keystone-locked blocks.