The Diamond of Purity is a gemstone fashioned by the sun-god Alaxar and gifted to King Anharos of Evenhold as a token of his favor. The stone radiates a dazzling light and cannot be safely touched or carried by evil beings.
Possession of the diamond imparts to the bearer a profound resistance to dark magic or attacks from beings such as demons, and magnifies the damage they can inflict on evil or undead creatures. Anharos and the Knights Adamant with whom he shared the diamond's power put the abilities to use in the Great Battle of Darkness, during which individual knights would routinely fell many thousands of foes.
When Anharos died in 49 YA, the diamond was entombed with his mummified body in the necropolis of Carthianum.
