DeYoung Red Diamond

The cause of the extremely rare deep red color of certain diamonds is not understood, but might be related to defects in the crystals' atomic structure. The DeYoung Red Diamond is one of the largest known natural red diamonds. It is a modified round brilliant cut diamond graded by the Gemological Institute of America (GIA) as VS-2 in clarity and natural fancy dark reddish brown in color, weighing 5.03 carats. In the late 1930s or early 1940s, the diamond was acquired by S. Sydney DeYoung, a Boston jeweler, mounted in an estate scarf pin set with a dark brownish-red stone that everyone assumed was a garnet. DeYoung realized on closer inspection that the red stone was not a garnet but a diamond. He removed the stone from its setting, kept it in a vault, and never offered it for sale. DeYoung decided to bequeath the diamond to the Smithsonian, and it was officially accessioned into the National Gem Collection in December 1987.