Dragon Balls

Dragon Balls are the namesake artifact of the Dragon Ball series. They are orange, crystalline spheres with the ability to call forth the Eternal Dragon Shenron who has the ability to grant wishes to anyone who gathers all seven of them. 
Unlike other forms of fiction that involve wishes being granted, the Dragon Balls seem to grant a wish exactly as the wisher imagined it, rather than warping the wish so that it is technically granted, but ends up making the wisher's life even more difficult.
Dragon Balls come in sets of seven with each ball containing the number of stars that signifies its respective number in the set.