- You may be looking for the individual from The Ultimate Adventure.
Crystals had a great variety of valuable (and in some cases, strange) uses.
Crystals with unusual properties
Radiation and/or luminiscence
Time travel and time manipulation
Certain crystals could focus and/or harness psychic energy. The people of Manussa used the Great Mind's Eye, a crystal artificially created in zero gravity, to accidentally create the demonic Mara. The Little Mind's Eye destroyed the Mara. (TV: Snakedance)
- The Eternity Crystal was a crystal of immense power created by the Darksmith Collective for the Krashoks which was capable of reanimating life. (PROSE: The Dust of Ages-The End of Time)
Other uses for crystal
Behind the scenes
According to the audio play adaptation, Seven Keys to Doomsday, the Crystal of All Power, capable of good or great evil, destroyed the Masters of the planet Karn. Consequently, the Masters broke the crystal into seven small crystals scattered across the planet, which the Daleks sought to implement their Doomsday Plan. The Fourth Doctor, or a version played by Trevor Martin, also sought the pieces. This wiki considers neither Seven Keys nor the original play, Doctor Who and the Daleks in Seven Keys to Doomsday, a valid source.