British billionaire and diamantaire Laurence Graff paid $53 million for the 1,109-carat Lesedi La Rona, the largest gem-quality rough diamond discovered in more than a century. Graff's purchase marks the poignant reunion of two of the world's largest and most high-profile diamonds. You see, Graff had already paid $17.5 million for the 373.72-carat "chunk" that […]