Background: Guastadisegni, 42, was 14 years old when his family moved from Italy to Chicago. He studied mechanical engineering at the University of Illinois at Urbana-Champaign, and studied ...

A mysterious black diamond stumped experts for years until one Belgian cutter invented a new machine to shape the 612-carat gem into the world's largest.

Mike Botha, 67, is an internationally acclaimed master diamond cutter with nearly five decades of experience in the profession. He was recently commissioned to craft one of the largest rough diamonds ...