He gave it away to Angelica, the Jewel of Necromancy was used in conjunction with other items for her to use on herself, bringing her back from being an undead lich to regain her life (same labyrinth she came from as its ruler) if you were referring to ch.48
As for Saint of Healing Faleria, different item was used to assist in her case (same dungeon from underneath the church) a few chapter ago