The Logan Sapphire sits heavy in its brooch, a stone the size of a large egg, but far more consequential. Weighing in at 422.98 carats, it measures nearly two inches long and one and a half inches wide. This isn’t just any sapphire. It’s a mixed cushion-cut gem, a rounded rectangle of deep blue with the faintest whisper of violet. The cut, crafted not for brilliance but to showcase the stone’s rich color, holds the eye with an intensity only nature could produce. Verified by the Gemological Institute of America in 1997, the Logan’s color is all its own, untouched by the heat treatments that often enhance lesser stones. Its reddish-orange fluorescence under ultraviolet light tells of trace amounts of chromium—an element, a story, embedded in the sapphire’s structure.

Set in a brooch of silver and gold, the Logan Sapphire is encircled by twenty diamonds, each one round, brilliant, and yet only a supporting act to the main attraction. These diamonds, 16 carats in total, likely came from an antique bracelet or necklace, repurposed to frame the sapphire’s grandeur. Its origin lies in Sri Lanka, the storied “City of Gems,” where it was mined from the earth, perhaps from the rich grounds of Ratnapura. Legends—some true, some imagined—trace its path through time. The gem passed from the hands of Sir Victor Sassoon, 3rd Baronet of Bombay, to the American diplomat M. Robert Guggenheim, who purchased the gem in the early 1950s.

Guggenheim gave the sapphire to his wife, Rebecca, as a combined Christmas and anniversary gift in 1952. Overwhelmed by the stone’s size and beauty, Rebecca wore it sparingly, only for the grandest of occasions, with the weight of the gem balanced by a shoulder strap. After Robert’s death in 1959, Rebecca donated the sapphire to the Smithsonian Institution, ensuring its place among the world’s most treasured gems. She insisted it be worn only by the First Lady of the United States, a gesture of both generosity and control, though it has never been used for this purpose.

In 1962, after remarrying and taking the name Logan, Rebecca saw the sapphire renamed as well. It became the Logan Sapphire, a title it carries in the National Museum of Natural History’s National Gem Collection, where it has been on display since 1971. The largest mounted gem in the collection, it’s a stone that transcends its origins, its value measured not just in carats, but in the weight of history, memory, and the whispered secrets of its former owners.