talisman

talisman \TAL-is-muhn, TAL-iz-muhn\, noun:

1. an object, such as a ring, engraved with figures supposed to have magic power; charm
2. anything that seems to produce extraordinary results

Cheadle, who is one of the film's producers as well as its star, is deployed like an ethical talisman to show viewers that this movie is not like those other terrorist flicks.
-- Philip Kennicott, The Washington Post, 2008-08-29

Included, almost as a talisman, is the 1905 painting of Two Harlequins, one of the few survivors of the Thannhauser Paris collection.
-- Time, 1965-05-07

by 1599, from French talisman, in part via Arabic tilsam (pl. tilsaman), a Greek loan-word; in part directly from Byzantine Greek telesma "talisman, religious rite, payment," earlier "consecration, ceremony," originally "completion," from telein "perform (religious rites), pay (tax), fulfill," from telos "completion, end, tax."