Best Ways to Farm Eridium in Borderlands 4 and How to Use It

Eridium is an indispensable currency in Borderlands 4. Most often, it appears as ingots of mysterious purple ore with many unique properties tied to the game's lore. As in previous entries of the series, this ore has a special purpose in Borderlands 4. In this guide, we’ll explain where to find Eridium and how to use it properly.

The use of Eridium in Borderlands 4 is significantly different from previous games. Now, the ore can be spent on rematches against enhanced versions of bosses — to do this, select the "Big Bis" mode (it becomes available after completing the main storyline) at Moxxi’s machine. Additionally, after the credits, you unlock the ability to more flexibly customize your character’s skills and perks — you can access this feature through the hero respec machine.

Another way to spend Eridium is firmware transfer. This new mechanic allows you to transfer a special bonus from one piece of equipment to another, destroying the original weapon in the process. Both money and Eridium ingots are required for firmware transfer.

The most obvious way to obtain Eridium is by killing special enemies. Along with a colorful fountain of all sorts of gear, purple ingots sometimes drop. In the later stages of the game, this type of loot will appear much more frequently.

Contracts are small optional quests that reward you with experience, money, and various in-game items. Eridium can also be a reward for some contracts. You can pick up these quests at any of the world’s safehouses.

On the main menu screen, there is a list of challenges. These are simple tasks that are often completed automatically as you play through the game. As a reward for completing a challenge, you can receive purple ore.