The Koh-i-Noor was a diamond owned by Queen Victoria, among others. There was a myth that whoever owned the diamond must surely die. Albert, the Queen's husband, constantly had it cut down for it to meet the exact specifications he needed for the light chamber.
In 1879, while being taken to a jeweller to have the stone recut, it was used in combination with the light chamber to kill a Lupine Wavelength Haemovariform. While inspecting it, the Tenth Doctor claimed that it was worth "the wages of the entire planet for a whole week"; Rose Tyler jokingly said that Jackie Tyler would fight the werewolf with her bare hands for it, the Doctor adding that she would win. (TV: Tooth and Claw)