The Uncle Sam Diamond May Be America’s Best-Kept Secret
Are diamonds found in the United States? It might surprise you, but the answer is yes. While the U.S. may not be the first place that comes to mind—countries like Botswana, Canada, and Australia typically top that list—America has its own surprising diamond legacy. At the center of it is the Uncle Sam Diamond, the largest rough diamond ever discovered in the United States and one of the most iconic stones in American gem history.
Few people realize that the largest rough diamond ever found in the United States was discovered not in a remote mine, but in Arkansas, a state where visitors can still hunt for diamonds today. Natural diamonds have been unearthed in just a handful of regions across the country, most notably Arkansas and Colorado. Although commercial mining efforts never truly took off, the discoveries made there include remarkable stones that rival famous diamonds found anywhere in the world.
Below, discover the fascinating stories behind the Uncle Sam Diamond, the Freedom Diamond, and other rare natural diamonds found in the United States.
Meet the Expert
- Grant Mobley is the Jewelry & Watch Editor of Only Natural Diamonds.
- He is a GIA Diamonds Graduate.
- He has over 17 years of jewelry industry experience, starting with growing up in his family’s retail jewelry stores.
The Uncle Sam Diamond
| Weight: | 12.42 carats |
| Colour: | Pinkish-brown |
| Cut: | Emerald |
| Country of origin: | United States |
| Mine of origin: | Crater of Diamonds State Park |
| Discovered: | 1924 |
| Value: | Considered Priceless |
| Current Location: | Smithsonian Museum |
The Uncle Sam Diamond: America’s Largest Rough Diamond Discovery
The Uncle Sam Diamond is a flawless 12.4 carat pinkish-brown emerald cut. The diamond was discovered at Crater of Diamonds in 1924. The 40.23 carat rough diamond crystal the Uncle Sam Diamond was cut from remains the largest rough diamond found in the United States.
After its discovery, the stone was held by Washington Roebling Schenck until he death in 1955, and it was then acquired by Boston jeweler Sydney DeYoung. In 1958, DeYoung sold the gem to New York jeweler B. Beryl Peikin, whose family kept it until 2015. In early 2019, J. & S. S. DeYoung Inc. obtained the diamond from the Peikin estate and shortly after sold it to Dr. Peter Buck, co-founder of the Subway restaurant chain. Recognizing its cultural significance, Dr. Buck purchased the Uncle Sam Diamond for donation to the Smithsonian Institution, ensuring it would remain a national treasure for generations to come.
Mineralogist Jeffrey Post, the museum’s Curator-in-Charge of Gems and Minerals says, “Amazingly, the Uncle Sam and Freedom diamonds were donated to our national collection within a month of each other. The generosity of the donors ensures that these great Earth treasures will forever belong to the people of the United States and the world.”
The Freedom Diamond: The Largest Cut Diamond Found in the U.S.
Two of the most notable diamonds found in the United States are the Freedom Diamond and the Uncle Sam Diamond. To this day, the Freedom Diamond is the largest cut diamond found in America and was discovered in the Kelsey Lake Diamond Mine in Colorado in 1997. It is a 16.86-carat, cushion-cut diamond now set in a beautiful three-stone ring.
The stone was cut from a rough diamond crystal weighing 28.20 carats. The Kelsey Lake Mine, where it was discovered, was opened in 1996 but was never commercially successful, meaning not enough diamonds were found to keep it operational. Even though it closed five years later, the fascinating mine left us with a few incredible American diamonds. The mine also remains the only modern diamond mine in American history.
The Crater of Diamonds: Home of the Uncle Sam Diamond
Crater of Diamonds State Park in Arkansas sits atop a 95-million-year-old volcanic deposit. The volcanic rock is lamproite as opposed to the much more common kimberlite. The diamonds here formed more than 1 billion years ago in the cratonic root of the continent and were brought to the surface by the volcano’s magma. After decades of trying to create a commercially viable and profitable diamond mine at the location proved unsuccessful, it was sold to the State and turned into a State Park in 1972.
The unique conditions and millions of years of erosion mean that, unlike the vast majority of diamonds, these can be found at or just a few inches below the surface. Crater of Diamonds State Park is now famous for its 37.5 acre field on which visitors can hunt for diamonds. On average, visitors discover roughly two diamonds per day, making Crater of Diamonds State Park the only public diamond site in the world where guests can search for and keep any diamonds they find.
The Canary and Colorado Diamonds:
Other Natural Treasures Found in the U.S.
Beyond the Freedom and Uncle Sam Diamonds, other notable American finds include two that have been left in their rough form: the Canary Diamond and the Colorado Diamond.
The Canary Diamond is a golden-yellow diamond crystal weighing nearly 18 carats and is one of the largest uncut diamonds from Arkansas. The Colorado Diamond is a 6.5 carat rough diamond that displays a near-perfect, natural, eight-sided (octahedral) shape.
The Canary and Colorado diamonds are part of the Smithsonian’s unrivaled diamond collection, which includes one of the world’s most famous gemstones, the Hope Diamond.
Though the United States isn’t known as a diamond powerhouse, the rare stones discovered on its soil—like the legendary Uncle Sam Diamond and the radiant Freedom Diamond—prove that nature’s most precious treasures can turn up in the most unexpected places. From Colorado’s now-quiet mines to Arkansas’s hands-on Crater of Diamonds State Park, these finds offer a uniquely American chapter in the global story of natural diamonds.
