A ter'angreal in the form of a glass blacksmith's puzzle.

References (Possible Spoilers)#

  1. In The Path of Daggers
    1. TPoD,Ch4 - Elayne finds the glass blacksmith's puzzle while going through the Ebou Dari stash.
    2. TPoD,Ch20 - When Elayne tries the glass blacksmith's puzzle it leaves her dizzy and unable to sleep.