The ring is reportedly 35 carats; larger than Elizabeth Taylor's legendary rock from Richard Burton, larger than Beyonce's and Kim Kardashian's engagement rings combined. The legendary Hope Diamond is 45 carats.
"Wilfredo Rosado is the designer of the ring," says Isabel Gonzalez-Whitaker, deputy editor of Billboard Magainze. "He does a lot of celebrity jewelry. He has said it's one of the most challenging pieces that he's worked on, in part because he's really good friends with Mariah."
Rosad told Vogue he worked 12 hour days for two weeks to complete the ring.
Carey's fiancee is an Australian businessman and casino tycoon who has been married twice before. He is reportedly worth around $3.5 billion.
"This is such an exciting time for Mariah right now," says Gonzalez-Whitaker. "She has a residency in Las Vegas, she just got her star on the Hollywood Walk of Fame, and now she is engaged!"
The engagement comes less than a year after Carey told Michael Strahan that life as a single mom meant a slowdown in her social life.
"As a single mom, it's not like, oh, I'm going out tonight to do this and that. Occasionally, on rare occasion, I will. But it's much more about watching movies with the kids and having fun and reading their stories," she said.
Carey's ex and father of her four year old twins, Nick Canon, sent out a funny and warm message on Instagram.
There's no word yet on a date for the wedding, but if the ring is any indication it's likely to be a big celebration.