EXCLUSIVE: See Nick Cannon’s First Mother’s Day Gift for Mariah Carey

New mom Mariah Carey didn’t have to wait long to celebrate her first Mother’s Day. Just days after welcoming twins Monroe and Moroccan on April 30, the singer toasted her new life as a mom with a very special present from Nick Cannon: a 4-carat diamond and sapphire necklace 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. “Pink sapphires are bright and bold and diamonds are always so classic.” The sparkling piece, which also incorporates 14-karat white and rose gold, is valued at $12,000. Cannon, a longtime customer of Jason, was excited about his big surprise. “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.”