Carol Ferris makes her only appearance as Star Sapphire in the 1970s in Superman 261 (Feb. 73), in a story by Bates, Swan and Anderson.
The story also brings back the Green Lantern tavern, seen in an issue of Action Comics in the mid 60s. Superman is dealing with a criminal there, while Carol Ferris is flying overhead. Carol had last been seen in Green Lantern, cancelled a few months earlier. She had learned about her Star Sapphire persona, but seemed to have things under control. This story has her go totally nuts. The destruction of the Green Lantern tavern becomes the death of Green Lantern himself in her mind, and she comes to believe Superman murdered him, for no apparent reason.
She is not in possession of her powerful gemstone, though. It is on display, along with a duplicate of her outfit, in Metropolis, where Lois Lane is doing a story on it. But Carol takes mental control of Lois, making her bring the sapphire to her office.
Lois is completely unaware of her actions, and somewhat embarrassed when Clark reveals the costume in her bag. But things turn deadly once Carol gets the gem back, and becomes Star Sapphire again.
The conclusion of the tale seems derived from Luthor’s Powerstone story. Carol puts the sapphire on a chain around Superman’s neck, and orders him to perform humiliating tasks.
Lois dons the spare outfit (Carol’s costume is manifested by the gem itself), and pretends to be the “real” Star Sapphire, giving Superman commands as well. Superman catches on to Lois’ plan, which involves him changing direction in the air, causing the chain to fall off of him.
The spell gets broken, and Carol winds up with no memory of what has happened.
Carol Ferris returns in a few years, in Green Lantern’s back-up series in the Flash, but does not become Star Sapphire again until the 80s. For the remainder of the 70s, there is a different woman, Debbie Darnell, who takes on that identity.