|First appearance||The Beast with a Billion Backs|
Diamondillium is a blue and ultra hard mineral created by Dr. Ogden Wernstrom. It was used to defend Earth from the tentacles of Yivo, but failed, as nothing in that universe could stop Yivo. There was a contest of Deathball between Professor Hubert J. Farnsworth and Wernstrom to decide whether diamondium or diamondillium would be used to do it. Wernstrom was the victor, so diamondillium was used (TBwaBB).