The planet produced gadolinium."
"Space Viking"
Henry Beam Piper
gadolinium was essential to hyperdrive engines; the engines of a ship the size of the Nemesis required fifty pounds of it.
"Space Viking"
Henry Beam Piper
We could charge our own prices for it, and we wouldn't need to tell them what gadolinium sells for on the Sword-Worlds."
"Space Viking"
Henry Beam Piper