databank
900 year diary
blue crystal
A crystal the Doctor took from Metebelis III. It had the ability to both cancel brainwashing and enhance intelligence. He gave the crystal to Jo Grant as a wedding present, but she returned it. Later, it magnified the latent psychic powers of an amateur mind-reader, killing him. The Doctor was forced to return the crystal to Metebelis III where The Great One, ruler of the Eight-Legs needed it to magnify her brain waves, making her ruler of the cosmos. Again, it fed the mental energy back at her, killing her. Along with other identical crystals, it was destroyed when her cave exploded.