talisman

n. (pl. -s) ring, stone, etc. Thought to have magic powers, esp. To bring good luck.  talismanic adj. [french and spanish from greek]

n. A magical figure cut or engraved under certain superstitious observances of the configuration of the heavens, to which wonderful effects are ascribed; the seal, figure, character, or image, of a heavenly sign, constellation, or planet, engraved on a sympathetic stone, or on a metal corresponding to the star, in order to receive its influence.