A weapon augment
Augments are a type of equipment in Xenoblade Chronicles X. They provide a benefit of some type, such as increasing a character or Skell's maximum Hit Points or making them harder to detect by enemies. Augments are similar to Gems in Xenoblade Chronicles.
Ground armor, ground weapons, Skell armor, Skell weapons, and Skell frames can have augments. Augments are not interchangeable between Skell gear and ground gear, but many augments have equivalents for both ground gear and Skell gear.
Some weapons and armor come with Battle Traits, built-in augments which cannot be changed. Others have slots for augments to be inserted into. After completing the mission Booming Business, augment slots can be added to equipment in exchange for Miranium.
Augments can be equipped from the gear menu by highlighting a piece of equipment with an augment slot, pressing X on the controller, and selecting Set Augments. Augments can be removed by pressing Y on the controller while inside the Set Augments menu.
Augments can be obtained as rewards for some Missions or obtained from Treasure Boxes, but most must be created at the AM Terminal in the Administrative District. Augments typically require Materials and Precious Resources to create. The AM Terminal can also be used to upgrade battle traits.
Augments are divided into five categories: Weapon Augments, Armor Augments, Skell Weapon Augments, Skell Armor Augments, and Skell Frame Augments.
Each category contains a number of Augment Types. Each Augment Type contains a number of Augment Effects. Augment Effects can be created at different power levels, denoted with Roman Numerals. The typical progression is I, V, X, XV, XX. Augments acquired through means other than crafting, as well as battle traits, can have power levels that fall between these numbers, such as Evasion Up III.