Swenyo
From Tardis Wiki, the free Doctor Who reference
Swenyo is a rare ore found on few planets. One of these planets is the planet Callous. It has a rare property of giving off psychic energy which can be used in battle computers. (AUDIO: Sins of the Father)
One of the few places it can be found is the Callous where The Master manipulated people and events to get a large deposit of it for the war effort.
When trying to mine the ore, races like the Ood are vulnerable to it and get driven insane by it. (AUDIO: Sins of the Father)
Even Timelords are effected by it, finding it uncomfortable. (AUDIO : The Persistence of Dreams)
