The columns are made of clear, glittering glass that rise up nearly one hundred feet into the air. They are arranged in concentric rings and are quite thin in comparison to their height. The glass columns are located near to Avendesora.
The experience of passing through the glass columns has been the one of the primary purposes of a visit to Rhuidean. For generations upon generations, those sent to the city are would-be leaders: aspiring clan chiefs and women about to become Wise Ones. Entry is traditionally prohibited to others, even with the barrier protecting the city broken and the Aiel now travel the city freely.
An Aiel man or woman, upon entering the glass columns, will experience the lives of some of the Aiel's oldest ancestors, learning the true origin of the warring race. The visions vary slightly for different people; a person sees pivotal events through the eyes of a direct ancestor. Those key events are the sharing of water with the ancestors of the Cairhienin, and the treaty of Rhuidean.
The Aiel leaders must learn, from these visions, that they descend from a people sworn to peace that betrayed their oath in order to be the violent clans of warrior societies today. The shame of this knowledge is too great for some people who pass through and those do not return to their people. Only one in three men survive the pilgrimage due to the experience of the columns. Muradin was one such man who did not survive.
A man who enters and emerges bears a golden dragon tattoo on one arm, the mark of a clan chief. However, when Rand emerged from the columns, both his arms bore the dragon tattoos: the anomaly is due to the fact that he is the Car'a'carn, the chief of chiefs.
A woman experiences the glass columns on her second visit to Rhuidean, at the end of her training as a Wise One apprentice. (The first time, she uses the three rings, another ter'angreal that shows different visions.) A woman does not bear a visual mark as a result of her time through the glass columns, and women accept the visions and therefore return to rejoin their clans more often than men.
The Aiel's use of the glass columns has always produced an experience of the past, but the ter'angreal has proved to have a wider function. The glass columns actually change the visions shown to correspond to the needs of the user, though it may only work for the needs of Aiel. When Aviendha journeys to Rhuidean the second time, after completing her first trip through the columns and seeing the history of the Aiels, she stops to observe them. After feeling compelled to walk towards them and touching them, wondering about the future of the Aiel and the use of the columns, now that all the Aiel know its secrets and that the Aiel's purpose as the People of the Dragon are nearly fulfilled. When she touches the columns and, instead of seeing the past as she had before, the ter'angreal shows the lives of future generations of Aiel instead, showing the genocide of the people by the Seanchan.
Questions of sentience
Aviendha, shortly before her re-entry of the glass columns, decided that she may be able to "read" how the glass columns work using her Talent that allows her to read ter'angreal. To do this, she needed to touch it. When she did, she experienced a strange event.
—Aviendha's thoughts while Reading the glass columns
Before she completed her first step away from the pillar, she experienced a vision from the pillar even though she did not step into the pillars. The vision successfully tempted Aviendha into entering the glass pillars for a second time. This vision did not seem to be caused by anything Aviendha did. The pillars seemed to act of their own will, giving the vision to Aviendha to force her to enter the pillars again.