Formula: Enchant Weapon - Spellpower

Source
This item drops from:
 * Magmadar in Molten Core
 * Baron Geddon in Molten Core
 * Lucifron in Molten Core
 * Shazzrah in Molten Core
 * Gehennas in Molten Core
 * Golemagg the Incinerator in Molten Core
 * Garr in Molten Core