The first necromancy spell Emerald Jewel learns, and his 5th spell overall, taught to him by Lord Sepulcher.

Ingredients

Any bone not attached to something living, or unliving.

Effect

The bone is turned into an almost liquid state and then reshaped into any form. Quality is dependant on the caster's skill with the spell, and the quality of the bone. Overuse of the same bone will eventually weaken it and make it brittle and unusable.
Knowing which bone it is, and what it came from also helps in shaping it correctly.