Star of Tarris
From Tardis Wiki, the free Doctor Who reference
The Star of Tarris was the power source for the Freeman of the House of Kark. It was lost on Earth and it took the Freemen decades before they could retrieve it. It was in the possession of William Hamilton's family for five generations, and was worn by Hamilton's wife when the Freemen tried to retrieve it. With the Third Doctor's help, the artefact was returned to them without bloodshed. (PROSE: Danse Macabre)