The 2000 Year Epic Campaign
Jewel of the Pillar
These mysterious jewels are what power the various pillars throughout the land. The are placed on a marking that us just above where the door would open. When the jewel is in close proximity that spot on the pillar the pillar will form an indentation to the jewel for it to be place. This is why no one had ever seen a slot for the jewel before. Once it is placed the pillar is essential turned on with the symbols lighting up, and a faint hum can be heard. Also, when someone is standing in front of it, the door will open. They are interchangeable, working on any pillar.
Session #5 (2nd Era) – The Champions of Elon found a full working one, the Aradesh Pillar and removed the jewel during the battle vs Merrshaulk. They repowered it and stood inside of it to see the interior.
Later they found another one, the Skyland Pillar. while Skyland briefly touched down to earth. Nearby they found another Jewel of the Pillar and powered up the Skyland Pillar before leaving. Rand agreed to say behind.
Session #12 (3rd Era) – When they were shown the Geargrind Island Pillar, Captain Jaffe powered up the pillar and briefly teleported back to Brind-Amor only to learn that they were in the process of shutting them down for the most part after the loss of the arcane researcher, Tinesia.