• The Egg of Mortal Essence
• Item Level 200Disenchants into:
  [Abyss Crystal]: 1
• Binds when picked up
• Unique
• Trinket
• Requires Level 80
• Equip: Increases spell power by 98.
  Equip: Your direct healing and heal over time spells have a chance to increase your haste rating by 505 for 10 secs.
• Vendor 40

Source

This item can be purchased in Dalaran for 40 from:

•  Arcanist Ivrenne <Emblem of Heroism Quartermaster>
•  Magistrix Lambriesse <Emblem of Heroism Quartermaster>
•  Debbi Moore <Trinkets & Charms>

Patch changes

• Patch 3.3.0 (08-Dec-2009): This item can no longer be triggered by Life Tap. 
  

External links

• Battle.net (EU)
• Wowhead
• Thottbot
• WoWDB