Heart of Ahriman

Literature
The Heart of Ahriman is a jewel that can defeat Xaltotun, found by Conan in The Hour of the Dragon. A Popular Fan theory is the heart was once the heart of one of the elephant headed creatures from Yag. It was shown that the "Heart of the Elephant" was an extremely powerful magic item in the Tower of the Elephant, also described as a red jewel.

Conan The Destroyer (1984)
Tamaris ruled the city of Shadizar and managed to convince Conan into helping her with the task of bringing her niece Jehnna on a perilous journey to retrieve firstly the Heart of Ahriman and then secondly the Jeweled Horn of Dagoth, with the empty promise of returning Valeria back to life as his reward.