A rare and diseased jewel, a canker fallen from the heavens
Fist sized diamond made famous by the thief Tolky. Stole the ‘rock’ from the Archmage Olikan and made it famous when his hidden thief’s den was found and destroyed by Olikan. The rock was never found though and Olikan searches for it to this day.
A certain country allows most civilians to carry weapons, but only if they are potentially deadly. Pepper sprays, stun guns/tasers, batons, and dart guns are banned. And if you kill someone and are not acquitted at trial, the punishment is to be hanged the day after you were found guilty. The message here is that if you want to go armed, you had better be prepared to risk killing someone and being executed unless it was clearly self defense.
When it comes to combat spells, again, only the highly dangerous can legally be cast with the same possible consequences if cast wrongly.