The Collector's Necklace is now upgradable!! The Blood Necklace collects your loot, and provides 10% increased luck on the Soul Room Chest. Upgrading the Collector's Necklace is the only way to obtain the Amulet of Blood. The upgrade is rated at an easy difficulty.
Unlike the collector's necklace, the Amulet of Blood is Untradeable.
Just like the Collector's Necklace, you get to choose what the amulet can auto loot for you: