The Tilonian pendant was a pendant worn by a common merchant on Tilonus IV.
In 2369, during a mission in which he was to locate and evacuate a Starfleet research team on this planet after the government fell into anarchy, Commander William T. Riker wore a pendant equpped with a communicator circuit. Later, after regaining consciousness, Riker grabbed the pendant, activated the circuit, and requested an emergency transport. (TNG: "Frame of Mind")