Greater Eternal Essence

Greater Eternal Essence is a magical essence of the Eternal plane used in Enchanting. One Greater Eternal Essence may be disassembled into three Lesser Eternal Essences.

Source
This essence is obtained by disenchanting level 51 to 56 items of Uncommon quality, the higher the less chance. Usually more from weapons (75% chance) than from armor (20% chance).

Greater Eternal Essence as a Quest Objective
The essence is required to complete the quest from Mux Manascrambler in Tanaris. This is part of the quest chain to convert Tier 0 to Tier 0.5.

Tailoring

 * Enchanted Runecloth Bag

Enchanting

 * Enchant Boots - Spirit
 * Enchant Shield - Vitality
 * Enchant 2H Weapon - Agility
 * Enchant Bracer - Mana Regeneration
 * Enchant Chest - Major Mana
 * Enchant Weapon - Agility
 * Enchant Weapon - Strength
 * Runed Arcanite Rod
 * Enchant Boots - Greater Agility
 * Enchant Bracer - Superior Strength
 * Enchant Gloves - Greater Strength
 * Enchant 2H Weapon - Major Intellect
 * Enchant 2H Weapon - Major Spirit
 * Enchant Bracer - Healing Power
 * Enchant Chest - Greater Stats
 * Enchant Weapon - Healing Power
 * Enchant Weapon - Mighty Intellect
 * Enchant Weapon - Mighty Spirit
 * Enchant Weapon - Spellpower
 * Enchant Weapon - Superior Striking