Enchanted Thorium Leggings

Source
This item is crafted by Blacksmiths with a skill level of 300.

The components are:
 * 10 Arcanite Bar
 * 20 Enchanted Thorium Bar
 * 6 Essence of Water
 * 2 Blue Sapphire
 * 1 Huge Emerald

The plans are a reward when you turn in to Lorekeeper Lydros in Dire Maul. Rattlegore in Scholomance drops the top half of the volume and the Crimson Hammersmith in Stratholme drops the bottom half.