Warp star

A warp star was a small diamond-like device that could create a powerful explosion. Jack Harkness described it as a warp fold conjugation trapped in a carbonised shell, or an "explosion waiting to happen".

Sarah Jane Smith was given a warp star on a pendant by a Verron soothsayer. After escaping Dalek captivity on the Crucible, she and Jack planned to detonate it to destroy the space station. However, the Daleks used a transmat beam to quickly remove Sarah Jane and Jack from the warp star, neutralising the threat. (TV: Journey's End)

Behind the scenes

 * Five different warp star designs were originally presented. This design used was chosen with Sarah Jane's character in mind.