The very first character to debut with the name Star Sapphire made only a handful of appearances during the Golden Age of Comics, and was actually an adversary to the Jay Garrick version of The Flash, not Green Lantern. This version of Star Sapphire, whose true name was never discovered, was a self-described queen hailing from the 7th Dimension, who tried to destroy the Earth by abolishing all plant life, thereby rendering the world without oxygen, leaving it uninhabitable by human beings. Decades later, it was revealed that this being had been selected to be Queen of the Zamarons, but her maniacal ways had showed her to be unworthy of the title, and she was banished to the 7th dimension.
Carol Ferris was the president of Ferris Air, and both the employer and girlfriend of test pilot Hal Jordan, who was secretly the Green Lantern of Earth. The pair had an instant attraction to each other, but their relationship got very complicated, when Carol was chosen to become the queen of an immortal race of alien warrior women called the Zamarons. These Zamarons were related to the same race which later evolved into the Guardians of the Universe, who were in charge of the Green Lantern Corps. As queen, Carol was given a powerful Star Sapphire gemstone, one that gave her powers comparable to any Green Lantern.
Despite being chosen as their new Queen, Carol did not want to leave Earth, because of her intense love for Jordan. Not willing to take no for an answer, the Zamarons brainwashed Carol into believing that Green Lantern was her sworn enemy. When Green Lantern managed to defeat her, the Zamarons deemed Ferris unworthy of being their queen, and removed her memory of ever having been the Star Sapphire, but they did leave behind not only the gem, which Hal kept in his possession, but also left Carol with a subconscious knowledge of her powers.
Another Star Sapphire would emerge during this era as well, when the Zamarons chose Dela Pharon from the planet Xanador as their new queen, and bearer of the Star Sapphire power, by giving her another gemstone, of which there were five total. However, a rival group of Zamarons insisted that it was Carol Ferris who should remain their rightful queen. Furious at the notion of another Star Sapphire, Pharon goes to Earth and attacks Carol, who once again becomes the Star Sapphire, and battles Pharon for the right to wear the crown.
Over the next several years, The Star Sapphire personality and powers would reemerge from within Carol from time to time, and she and Green Lantern would find themselves at odds. But with each encounter Hal Jordan would find a way to defeat the Star Sapphire personality and revert Carol back to normal, usually wiping her memory of the ever having been Star Sapphire at all.
During the 1970s, Earth was introduced to its fourth Star Sapphire, the alien from the planet Pandina named Remoni-Notra, who was newly chosen by the Zamarons to be their queen. Remoni-Notra was given one of the five Star Sapphire stones, and soon after she fled to Earth to try and find Carol Ferris and steal her gem as well. Upon arriving on Earth, she joined the Secret Society of Super Villains as the latest woman to go by the name Star Sapphire, and used her newfound abilities to try and locate Ferris.
Remoni-Notra took the alias Deborah Darnell during her time on Earth, and she became a stewardess at Ferris Aircraft, all in an effort to get close to Ferris in order to take her Star Sapphire gem from her and increase her powers. Debbie Darnell fought not only Green Lantern, but also the entire Justice League as a member of the Secret Society. Much like Carol did, she dated a Super-Hero, the adventurer called Captain Comet. She was eventually mind-wiped at the request by Hal Jordan in an effort to protect Carol Ferris from her.
Despite other women taking on the mantle of Star Sapphire, Carol Ferris kept getting drawn into its orbit time and again. When Carol had the Star Sapphire persona seemingly removed from her for good, she then developed a third subconscious identity, the so-called "Predator", which was male. Once it was physically separated from Carol, the Predator began to seduce her, as she was oblivious to the fact that it was ever a part of herself. Eventually, Hal Jordan defeated the Predator in battle, but was helpless to stop it from merging with Carol into Star Sapphire once again. Eventually, the Predator returned, and revealed that he was actually an ancient parasite from the planet Maltus. He then transformed Carol into a fully evil version of Star Sapphire, who eventually murdered Green Lantern Katma Tui, wife of Green Lantern John Stewart.
Eventually, the Predator and this iteration of Star Sapphire were completely separated from Carol, and Carol discovered that she and Star Sapphire were in reality two separate beings, and Sapphire wasn't merely Carol transformed, but an entity who actually took possession of her body. Believing she was finally free for good, Carol then attempted to put her romantic past with Hal Jordan behind her, and married someone else. But she never truly got over her feelings for Hal Jordan, and ultimately this marriage ended in divorce.
The next Star Sapphire was another one of Hal Jordan's girlfriends, a fellow Air Force pilot Jillian Pearlman, who went by the nickname "Cowgirl." When Carol once again became Star Sapphire when the original gem resurfaced, she attacked Cowgirl, but the Star Sapphire gem left Carol again and possessed Cowgirl instead, drawn towards her intense feelings for Hal Jordan. It was during this time that Carol learned that the gem taps into her feelings of love, much like a Green Lantern ring taps into the wearer's willpower.
Hal Jordan was able to remove the Star Sapphire from her being, but not long after, four representatives of the Zamaron race offered both Cowgirl and Carol Ferris membership in their newly created Star Sapphire Corps, also known as the Violet Lanterns. The five Star Sapphire gems were deemed to uncontrollable for any one person to wield, so they were combined into a central power battery, and then individual power rings would channel their energy, just like Green Lantern rings did.
Although at first Carol declined to become a member of the Star Sapphire Corps, she later reluctantly chose to wear the ring when she was informed about the forthcoming Blackest Night, and that her beloved Hal was supposed to die in this event. Only the combined light of the different emotional spectrums could stop the Black Lanterns, so Carol accepted the responsibility in order to save Hal. Carol was now part of a larger group of Star Sapphires, who tried to wield their love energy to do some good in the universe.
In the wake of 2011's FLASHPOINT event, a new villainous Star Sapphire entered the picture, one who would seek to undo all the good the Violet Lantern Corps had done to redeem the Star Sapphire legacy. This deadly new Star Sapphire was the alien Prixiam known as Nol-Anj, a former prisoner of the Oan sciencells, jailed for a variety of different crimes. As time passed in her cell, she seduced her guard, a Green Lantern named Cossite, who fell madly in love with her. During an attack on Oa, a member of the Star Sapphire Corps who arrived to aid in the defense of the planet is killed in battle, and the dead Sapphire's ring flies to Nol-Anj, and she becomes a Star Sapphire herself.
Although Cossite believes that her being chosen is proof that she loves him, she then kills him once she if free of the cell, telling him in his dying moments that the love the ring detected inside of her was not for him, but for her clan on her homeworld. She then flees for space sector 0563, home of her clan, a group of scavengers and pirates, who then make her their queen. This new Star Sapphire queen becomes an even deadlier threat to the galaxy than Carol Ferris or any of her other successors ever were, and a thorn in the side of the Green Lantern Corps.