DeYoung Red Diamond

The DeYoung Red Diamond is a 5.03-carat red diamond in the Smithsonian’s National Gem and Mineral Collection and is the third-largest red diamond known as well as the only one on public display. Unmounted and cut as a modified round brilliant, it has a deep red color with a slight brown tint, VS-2 clarity, and the rare Type IIa purity associated with diamonds lacking chemical impurities. Its modern history began when Boston jewelry seller Sydney DeYoung bought it at a flea market, where it was mistaken for a garnet on a hatpin. After testing confirmed its rarity, the diamond eventually passed to the Smithsonian after DeYoung’s death.

Washington, District of Columbia · United States