It Looked Like a Garnet but Turned Out to Be a $Million-Dollar Diamond

The DeYoung Red Diamond is a 5.03-carat Type IIa diamond graded by GIA as deep red in colour with a slight brownish hue and VS2 clarity. It ranks as the third-largest publicly known red diamond, only slightly smaller than the 5.05-carat Kazanjian Red and the 5.11-carat Moussaieff Red.

Unlike traditional round brilliant diamonds, this gem features a modified cut with horizontally split kite-shaped facets on the crown, which enhances its fire and brilliance.

The diamond is named after Boston jeweller Sidney DeYoung, who unknowingly purchased the gem in the 1930s–1940s as part of a scarf pin from an estate sale. At the time, it was mistaken for a garnet or ruby. Years later, it was revealed to be a rare red diamond—and is now part of the Smithsonian’s famed gem collection.

What started as an overlooked accessory became one of the most remarkable red diamonds ever found—proving that not all treasures come with a spotlight.