Cadsuane's hairpiece is a ter'angreal. It likely prolongs her life and protects her under certain scenarios, providing warning, etc. She is never without it, and it felt cold against her head when another sister held the power in her presence (POD). ...

One quick theory. I was re-reading A Path of Daggers last night and I noticed that when Cadasuane summoned Alanna, and threatened her, Alanna filled herself up with the One Power, and, here's the kicker... The amulet on Cadsuane's head got cool. Jord...