• Holy Mightstone
• Item Level 50Disenchants into:
  Not disenchantable
• Binds when picked up
• Use: Shatters the Holy Mightstone, granting 300 attack power and increasing Holy damage from spells and effects by up to 400 when fighting undead. Lasts 10 min.
• 1 Charges

Source

This item is a quest reward from  [52D] Forging the Mightstone^ω τ ϖ.

Patch changes

• Patch 1.8.0 (10-Oct-2005): Added. 
  

External links

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