Core of Earth

The Core of Earth is an elemental part of Azeroth and is useful in crafting powerful items.

Core of Earth as a quest item
Core of Earth is needed for the following quests:
 * Elemental Leatherworking (Alliance) (Alliance)
 * Elemental Leatherworking (Horde) (Horde)

Core of Earth as an ingredient
Core of Earth is used in the following recipes:

Blacksmithing

 * Earthforged Leggings
 * Light Earthforged Blade
 * Runed Mithril Hammer
 * The Shatterer

Engineering

 * Lil' Smoky
 * Ultrasafe Transporter: Gadgetzan

Jewelcrafting

 * Figurine - Truesilver Crab

Leatherworking

 * Volcanic Leggings

Enchanting

 * Enchant Cloak - Greater Resistance