Madranite one-five

Madranite one-five was a mineral abundant on the planet Calufrax, which, according to the Fourth Doctor, was the only place it was known to occur naturally.

The vibrations of refined madranite one-five and voolium crystals could be used to power a psychic interference transmitter, and the presence of these two minerals brought Calufrax to the attention of the crew of the pirate planet Zanak, who needed it to neutralise the psychic powers of the Mentiads. (TV: The Pirate Planet)

Mandranite was mined in the star system of Orion Beta. Ford Prefect used to play drinking games in hyperspace ports which served the mandranite mining belts there. (NOTCOVERED: The Hitchhiker's Guide to the Galaxy)

Behind the scenes

 * Both mentions of madranite, one in Doctor Who and one in The Hitchhiker's Guide to the Galaxy, were written by Douglas Adams.