The 46-year-old singer showed off the bling as she enjoyed a catch up with friends - including her choreographer and backing dancer Bryan Tanaka, who Packer was allegedly 'jealous' of.
According to TMZ, she is insisting upon a $50million pay off from Packer.
Mariah is said to think he owes her for uprooting her two children from New York to Los Angeles, so Packer could be near his own children.
The report claims Packer also made financial promises to Mariah during their romance, which she wants him to fulfil.
Not that Mariah was letting the stress of her break-up show on Thursday night, as she partied with her closest pals - including dancer Bryan.
Bryan is reported to be at the centre of the break-up, with James reportedly using his status to get him 'banned from Caesar's Palace', where the songstress has a residency, MailOnline reports.