This diamond is named after Major Alfred Ernest Allnatt. He was one of the holders of the diamond. The Allnatt diamond has size of 101.29 carat (20.258 g) with a cushion cut. The diamond color is rated as fancy vivid Yellow by the Gemological Institute of America. No one know precisely where the diamond was found. But some expert say that the diamond was found where the De Beers premier diamond mine now located.