It modifies a Map item adding layers of Delirium with the
Essences Currency reward type. Right click this item then left click a Map item to apply it. Can apply up to 5 to a single Map item. Shift click to unstack.
An essence is part of a complex group of currency items used for crafting equipment. All essences can be used to upgrade a piece of normal rarity equipment to rare and apply one guaranteed affix. Some essences can also be used to reforge the affixes of rare equipment.
WARNING: Despite the similar wording to Chaos Orbs, using an essence on an item with a meta-crafting mod (Prefixes Cannot Be Changed or Cannot roll Caster Modifiers) will ignore that mod and overwrite existing prefixes and suffixes ignoring any restrictions.