Zelanite
From Tardis Wiki, the free Doctor Who reference
Zelanite was the name of a mineral that was found on the planets Lucifer and Kaldor.
It was one of the many valuable elements found in the sands of Kaldor and the inhabitants made use of Sandminers to extract it as well as other minerals. (DW: The Robots of Death, DWM: Crisis on Kaldor)
Lucifer had a sea of liquid zelanite that the angels danced in. (NA: Lucifer Rising)
