The glass bracelet is a ter'angreal that was stolen from the White Tower by the Black Ajah.
Appearance[]
The bracelet is made of glass rings that are unbreakable by almost any force.
Use[]
The bracelet is a sleepweaver, allowing the user to enter Tel'aran'rhiod by channeling Spirit into it.[1]
History[]
This sleepweaver was used by Temaile to spy on Elayne and Nynaeve in Tel'aran'rhiod. She reported to Asne, Chesmal and Eldrith that the girls were, indeed, in the Royal Palace.
After Temaile was captured it is presumed that the glass bracelet was rescued by Elayne.
After Sheriam stole almost all the sleepweavers in the rebels camp, Egwene asked Elayne to reproduce as many as she can from the sleepweavers in her custody, so probably Elayne made one or more copies of the glass bracelet