Earth Armor is a chestplate that grants 16 armor units, or 8 chestplates, and grants an increase in unarmed combat(punching without an item in your hand). It has a magical ability to repair itself at the cost of mana. this cost depends on how damaged the chestplate is, and how frequently you are getting hit, costing more mana the more damaged it is.
The Earth armor gives, like the Battlemage armor, protection from most damage sources, for example, magic damage from spells (and potions) and essentially makes you invulnerable when paired with (enchanted and/or imbued) Battlemage armor. But the Earth armor also takes damage on its durability much faster than any other armor will (possibly due to it absorbing much more damage too) and as such, you should be wary of its durability in a fight and retreat when it does.
How to Obtain
The Earth Armor is a common drop from the Earth Guardian, the second lowest level boss. Only a few kills on the Earth Guardian are likely to be required before a drop of the Armor, and it is currently untested as to whether the looting enchantment has an effect. (Source Personal Testing)
With Other Armor
The Earth Armor is powerful on its own, but it can also be paired with other armor. a full mage armor set will grant a full bar with 24 units, and Battle mage armor will provide 28 units.
The Earth armor has the Soulbound I enchantment when dropped from the Earth guardian and even if you remove the enchantment, you can't enchant it. It is however possible to add enchantments to it with an anvil and an enchanted book.