(13.50 g) cushion-cut black diamond , also called the Eye of Brahma Diamond . Blue Heart Diamond 30.82-carat (6.16 g) heart brilliant. Part of the Smithsonian collection. Briolette of India Diamond 90.38 carats (18.08 g) - possibly the oldest diamond on record. Centenary Diamond 273.85 carats (54.77 g), modified heart-shaped brilliant, the world's