Allnatt Diamond

Weight
101.29 carats (20.258 g)
Color
Fancy Vivid Yellow
Cut
Cushion
Country of origin
probably South Africa
Mine of origin
probably Premier Diamond Mine
Date discovered
unknown (pre-1950s)
Cut by
several
Original owner
Alfred Ernest Allnatt
Current owner
SIBA Corp.
Estimated value
at least USD 3 million

The Allnatt Diamond is a diamond measuring 101.29 carats (20.258 g) with a cushion cut, rated in color as Fancy Vivid Yellow by the Gemological Institute of America. This diamond is named after one of its holders, Major Alfred Ernest Allnatt, a soldier, sportsman, art patron and benefactor. While it is not known precisely where the Allnatt originated, many experts believe that it was probably found in what is now known as the De Beers Premier Diamond Mine.
The Allnatt's origins are unknown prior to Major Allnatt's purchasing of the diamond in the early 1950s. After purchasing the diamond, he commissioned Cartier to make a setting for it. The final setting was a platinum flower with five petals, a stem and two leaves, all set with diamonds. The Allnatt was resold at auction in May 1996 by Christie's in Geneva for $3,043,496 US. At the time of its sale the Allnatt was 102.07 carats (20.414 g). and was graded Fancy Intense Yellow. After being sold to the SIBA Corporation, the diamond was re-cut to its current weight and the intensity was upgraded as a result.
The Allnatt was displayed as part of the Smithsonian's "The Splendor of Diamonds" exhibit, alongside The De Beers Millennium Star and The Heart of Eternity.