The amulet is most famous because of its ability to make the bearer entirely immune to Arcane and Holy damage, helping greatly in battles with Arcane Enchanted monsters, including the Rift Guardian Eskandiel.
Unlike other similar amulets, it heals the character for 20-25% of damage prevented instead of 10-15%.
Stats (Level 31)
Countess Julia's Cameo
"Countess Julia attempted to put down the Cartolus Insurrection with her own personal guard, in an attempt to impress Justinian III. The effort failed miserably, as her guard was slaughtered and the uprising spread. Only the countess's enchanted cameo enabled her to survive this folly. It did not save her life, however, as King Justinian was so displeased, he had her tortured and then executed." —The History of Westmarch