• Shard of Woe
• Heroic
• Item Level 379Disenchants into:
  [Abyss Crystal]: 1-2
• Binds when picked up
• Unique-Equipped
• Trinket
• Requires Level 85
• Equip: Reduces the base mana cost of your spells by 405.
  Use: Increases your haste rating by 1935 (15.11% @ L85) for 10 sec. (1 Min Cooldown)
• Sell Price: 8 5 7

Source

This item drops from Sinestra in the Bastion of Twilight raid instance on heroic mode.

Patches and hotfixes

• Patch 4.0.3a (2010-11-23): Added. 
  

External links

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