Pumpernickel

[Benjamin Fortson]

Both metals nickel and cobalt are named for spirits or goblins that were
imagined by miners to have stolen more valuable metals (copper and silver,
respectively) and replaced them with the less valuable nickel and cobalt.
Kobalt is a variant of Kobold, a type of spirit or mischievous goblin;
nickel is short for Swedish kopparnickel, with Nickel the name for a kind
of ghost said to visit children on the eve of St. Nicholas's Day. Miners at
an earlier period thought that nickel was a copper alloy and would try in
vain to extract copper from it.

Ben