Whispering Crystal
A tiny, translucent gem that emits a soft hum. When activated, it allows the user to send a short telepathic message to another creature within 60 feet. Usable 5x day.
I really do try to make most of this original, but since Forgotten Realms is an integral part of the world I can't help if anything is used without formal permission, but is still "fair use" as I am just using this for my private games.