Heart of Aszune

The Heart of Aszune is a magical amulet. Legends say that the imprisoned spirit of Aszune seeks out her heart to this very day. The essence of the heart, called Essence of Aszune, came somehow to Dalaran.

Source
Thrall can find this in The Oracle, chapter 7 of the Warcraft III orc campaign, The Invasion of Kalimdor.

El Corazón de Aszune