The Moussaieff Red Diamond

The Moussaieff Red Diamond is a diamond measuring 5.11 carats (1.022 g) with a triangular brilliant cut (sometimes called a trillion or a trilliant cut), rated in color as Fancy Red by the Gemological Institute of America. While this may seem relatively small when compared to other famous diamonds, the Moussaieff Red is, in fact, the largest Fancy Red the GIA reports having rated.

The Moussaieff Red is reported to have been found by a Brazilian farmer in the Abaetezinho river in 1990, in a region known as Alto Paranaiba which has a reputation as a source of large and fancy-coloured diamonds. In the rough, it is believed to have weighed 13.9 carats (2.78 g). The diamond was purchased and cut by the William Goldberg Diamond Corp., where it went by its original name the Red Shield. It is currently owned by Moussaieff Jewellers Ltd.

The Moussaieff Red was displayed as part of the Smithsonian's "The Splendor of Diamonds" exhibit, alongside The De Beers Millennium Star and The Heart of Eternity.