Arcalum

Arcalum is a coarse, twilight-blue mineral powder found in underground deposits, especially in the Dream Realm. It can be used to aid in enchanting. It is usually measured in bullets; a single bullet of arcalum has about the volume of a square cubit. The name "bullet" most likely refers to the bulletlike shape of the phials often used to carry the mineral.

Origin
Arcalum is believed to be a result of organic matter decaying and being compressed under miles of earth and stone for thousands of years, similar to the way that oil and coal form; however, arcalum is formed from the remains of magical creatures, rather than mundane ones.

Uses
Arcalum is most commonly used in enchanting, where it is applied to the object to be enchanted before the actual ritual of enchanting commences. The application of arcalum reduces the object's resistance to magic, thereby making it easier to enchant.

Arcalum is also used to smelt auralladium. Thus far, it is the only known material that can do so.