The Amber Plaque is a ter'angreal that was stolen from the White Tower by Liandrin's Group of Black Sisters.
The ter'angreal seems to be made of amber. It bears the image of a sleeping woman on it.
It is a sleepweaver. By channeling spirit into the plaque and falling asleep, the user can enter Tel'aran'rhiod.
This sleepweaver was recovered from the Black sisters Amico and Joya in Tear. Elayne made many copies of it.