Opaka's pendant
A pendant was a piece of jewelry often combined with a necklace or an earring.
On Tilonus IV, common merchants wore Tilonian pendants. (TNG: "Frame of Mind")
Kai Opaka gave Miles O'Brien her pendant shortly before she left Deep Space 9 in 2369. She told him that it was meant for his daughter. (DS9: "Battle Lines")
In 2370 on Barkon IV, the blacksmith Skoran made a pendant out of radioactive metal. It was purchased by Garvin and given to his daughter Gia, who then started to suffer from radiation poisoning. Data later used this pendant to demonstrate the existence of radiation and how to block it. (TNG: "Thine Own Self")
According to Harry Kim in 2371, a Lobi crystal offered by Quark would have made a great pendant for his mother. (VOY: "Caretaker")