Hexical Essence is an item used to make Hexical Diamonds, which are essential in crafting pieces of the three Hexxit Gear Armor sets (Tribal, Thief, and Scale). Four Hexical Essences and one diamond are required to make each Hexical Diamond. One Hexical Diamond is needed for each Hexxit Gear armor piece.
Acquiring Hexical Essence
The essence can be harvested from the Hexbiscus flower. It is an extremely rare flower, which can be found in the Jungle, Plains, Snow, and Forest biomes. You can sometimes find Hexical Essence in chests in dungeons, though it is quite rare. It is also sometimes dropped by Infernal Mobs.