"It looks like a radiant cut center diamond, approximately 8 carats," jewelry designer Peter Meksian from Michael M. tells Us Weekly of the We're the Millers star's new bauble. And it appears that sexy screenwriter-actor Theroux, 41, didn't spare any expense for his love of a year and a half. Says Meksian: ""Estimated price tag for a top quality diamond of this size: $500,000."
Pitt, 48, proposed with all six of their kids present. "Angelina cried and smiled," a source told Us Weekly. "Everyone hugged once she put [the ring] on. She went around and showed it to each of the kids."