This has SILVER AGE written all over it Stewart. and I LOVE the Hal Jordan GL reference even down to the oath of the Guardians of the universe...he's the GL I read in comics. But there is a female GL in the New 52 universe. Her name...Jessica Cruz
Ironically since Supergirl is supposed to be about love, there is an oath to Star Sapphire (aka Carol Ferris, Hal Jordan's love interest in one canon). She wears a violet ring but is sometimes a hero, sometimes a villain. Her oath...
For hearts long lost and full of fright,
For those alone in blackest night,
Accept our ring and join our fight,
Love conquers all-- with violet light!