Feedstock

Feedstock is one of the two ingredients required to enchant armor and weapons. Alkahest is the other required ingredient. Equipment requires feedstock of the same tier for the enchantment. (Tier 1 equipment requires Tier 1 Feedstock. Tier 3 equipment requires Tier 3 Feedstock.)

Feedstock was added in patch TERA: Fate of Arun. Before that pieces of gear were used to enchant gear, and relic shards for Avatar Weapons.

As level 65 gear changed with introduction of Guardian gear system, feedstock and alkahest is no longer used to enchant level 65 gear. It remained in use for leveling gear, until Avatar weapons revamp in July 2019 patch 83. Maximum tier of leveling equipment is 4 and therefore that is max tier of Feedstock needed (Note that equipment tier is not currently shown anywhere). Higher level feedstock was used for old level 65 endgame gear.

Acquisition
There are three main ways to obtain feedstock: Dismantling, Upgrading, and Purchase. There are some quests which will give feedstock as a reward.

Dismantling
Dismantling relic shards, armor, and weapons gives feedstock. The tier of equipment or shard the character dismantles will produce feedstock of the same tier. Dismantling is done by opening the character's inventory window, and selecting the lowest center icon (above the space for the amount of currency), then selecting the equipment that is able to be dismantled.

Upgrading
Feedstock can also be obtained by combining six lower tier feedstock into one higher level feedstock. (Six Tier 1 Feedstock can be combined to form one Tier 2 Feedstock.) If you use the Shift button when right clicking the stack of feedstock to be upgraded, a confirmation window will pop up with the maximum number of feedstock that can be upgraded in that stack. (If you have a stack of 6,000 Tier 1 Feedstock, the confirmation window will ask if you want to create the 1,000 Tier 2 Feedstock and will give you the option of typing in a lesser amount.)

Buying
Feedstock can also be obtained from the Trade Broker.

Enchanting
The suggested amount of feedstock to be used during enchanting depends on the bonus which is being attempted. The following is the suggested amounts for +1 to +9 levels of enchantment.

History
As of the patch TERA: Fate of Arun extraction (Metal Extraction, Cloth Extraction, Alchemy Extraction)  was removed and replaced with the Dismantle action. Feedstock has also replaced the constant need for relic shards, thus making it easier to enchant weapons and armor.