The Skofnung Stone is a magical stone used to sharpen the Skofnung sword.
Magnus Chase and the Gods of Asgard[]
The Hammer of Thor[]
Loki wanted to break free of his bonds. The bonds, being made of his dead children's intestines, were very sticky and corrosive. Any sword that would tear through one bond, even Sumarbrander, would be instantly rendered blunt and useless. The Skofnung sword could be sharpened with the stone as many times as desired, so that all the bonds could be broken.
The stone was in the possession of Alderman, Hearthstone's father. Loki forced Magnus and Hearth to get the stone to him. For this, Magnus and Hearth visited Mr. Alderman in Alfheim.
Magnus and Hearth had to do what Alderman asked for (a wergild to cover the whole of Hearth's carpet with gold coins), in return for the stone. This was needed because the stone is useful only if given freely. They used it to cure Blitzen.
Towards the end of the book, Randolph Chase used the Skofnung stone to sharpen the Skofnung sword, in order to free Loki. It's unknown what happened to the stone but it was likely destroyed when the sword dissolved.
Trivia[]
- The first mention of the stone is by Loki in the tomb of the wight, who describes it as "About yea big, blue with grey flecks", however upon being actually by Magnus and Hearthstone in Mr Alderman's mansion, it is described as "grey with blue flecks, just as Loki described" which is the opposite. This is probably a mistake.