*A week after welcoming twins Monroe and Moroccan on April 30, the singer got a very special Mother’s Day gift from Nick Cannon: a 4-carat diamond and sapphire necklace featuring the twins’ names – a creation from Jason of Beverly Hills.

“Nick was really excited about the babies’ names and wanted to do a piece with them for Mariah’s first Mother’s Day,” jeweler Jason Arasheben explains to People magazine. “Pink sapphires are bright and bold and diamonds are always so classic.”

The piece, which also incorporates 14-karat white and rose gold, is valued at $12,000.

“Nick came in and met with Jason on the Friday after his twins were born,” a source tells People. “He was bleary eyed, looking so tired but so happy — all smiles, saying he wanted to design something special for Mariah’s first Mother’s day. He couldn’t want to surprise her on Sunday.”