Red-letter day as gemologists discover why crimson diamonds are so rare

Red diamonds are among the rarest gemstones in existence, with only 24 stones weighing more than one carat documented worldwide. Recently, one of the most remarkable red diamonds, known as the Winston Red, was put on public display at the Smithsonian National Museum of Natural History in Washington, D.C. This exquisite gem, which was donated to the museum in December 2023 by Ronald Winston, the son of renowned jeweler Harry Winston, has fascinated gemologists and the public alike. Recent analyses have uncovered the unique characteristics that contribute to its striking crimson color, as well as insights into its origins. The research findings, published in the journal Gems and Gemology, indicate that the Winston Red contains a specific type of nitrogen and features a deformed crystal lattice composed of tightly packed layers ranging from pink to red.

The conditions required to form such a diamond are exceptionally intense, involving extreme heat and pressure, which further elucidates the rarity of these brilliant red stones. The Winston Red's history traces back to 1938, when it was sold by Jacques Cartier to the maharajah of Nawanagar in India. The combination of its chemical structure, its method of cutting, and historical records has allowed researchers to hypothesize that the diamond likely originated from diamond mines in Brazil or Venezuela. This investigation not only sheds light on the Winston Red itself but also enhances the understanding of the formation of red diamonds in general, a subject that has intrigued gemologists for decades.