Silver

Silver is a metal which, in human mythology, could be used to kill a werewolf, particularly in the form of bullets. Silver bullets were also utilised by the Brigadier to defeat the Destroyer. (TV: Battlefield)

The planet Megerra was rich in valuable minerals such as silver. (PROSE: Shakedown)

When forced to create EDTA to cure arsenic poisoning, Gwen Cooper used a number of ingredients in the antidote, one being silver. (TV: Rendition)