There is something quite unique about a star ruby (along with a star sapphire) in that it exhibits a star-like reflection of light, called asterism. This optical phenomenon is caused by small needle-like inclusions of rutile, a mineral, within the stone. The star pattern is symmetrical and shifts in the light, giving the impression of a star trapped within the stone. That's the technical stuff. The other thing is that they are just beautiful and the star follows your gaze whenever the turn it in front of you.
