Star Sapphire is the name of several fictional characters in DC Comics; many of them are villainous, and all connected in origin. Within DC continuity, an immortal race of warrior women (the Zamarons) were depicted as having the ancient tradition of choosing physically identical mortals from across the cosmos to serve as the host body for their queen. The woman chosen to serve this queen is called Star Sapphire. She is given the queen's symbolic weapon; a crystal resembling an actual star sapphire that grants the user powers similar to the power ring of Green Lanterns.
This page contains all about Violet Lantern Corps Oath.