What started as a casual family outing turned into a once-in-a-lifetime treasure hunt for one Minnesota man — who thought he was picking up litter but instead discovered a sparkling 3.81-carat diamond.
David DeCook, a long-time visitor to Arkansas’ Crater of Diamonds State Park, was walking through the park’s 37.5-acre search area on April 21 when something shiny caught his eye on the ground. Assuming it was a discarded candy wrapper glistening in the sun, he bent down — only to realize it was no ordinary trash.
“Once I saw a metallic, tinfoil-like shine, I knew what I had found,” DeCook said.
He calmly pocketed the unusual stone and later returned to the park to have it examined and officially registered. To his amazement, park staff confirmed it was a 3.81-carat brown diamond — the largest registered diamond at the park so far in 2025.
DeCook, from Stewartville, Minnesota, has visited the park for years with his brother Derek. While both have collected numerous smaller stones, none came close to this remarkable find.
“Oh, you’re going to be mad once you see what I found!” David jokingly told his brother after picking up the gem.
According to Assistant Park Superintendent Waymon Cox, the park received nearly an inch of rain just a day before DeCook’s visit. That’s important because the rain often washes away soil, revealing heavy minerals and diamonds on the surface.
“Many of the park’s largest diamonds are found on top of the ground,” said Cox. “As rain falls, it uncovers rocks, minerals, and diamonds near the surface.”
Meet the “Duke Diamond”
The stone — with its metallic copper hue and triangular, blocky shape — was named The Duke Diamond, in honor of DeCook’s beloved dog. As of now, DeCook says he hasn’t decided what to do with his dazzling discovery.
While brown diamonds typically fetch less than their white counterparts, they can still be worth thousands. Experts estimate brown diamonds can range from $1,000 to $5,000 per carat, putting the Duke Diamond’s potential value anywhere from $3,800 to over $19,000.
A Record-Breaking Year at the Park
DeCook’s diamond marks the 217th gem registered at the park this year, out of 220 total diamonds weighing more than 32 carats collectively. So far, only five of those have weighed over one carat, making the Duke Diamond a standout.
Before DeCook’s find, the most significant diamond discovery at the park was a 7.46-carat gem named the Carine Diamond, found by French tourist Julien Navas in January 2024.
Crater of Diamonds State Park is one of the only places in the world where the public can search for diamonds in their original volcanic source. Since 1906, over 75,000 diamonds have been unearthed there, including the famed 40.23-carat Uncle Sam diamond, the largest ever found in the U.S.
Whether you’re a gem enthusiast or just enjoy the outdoors, David DeCook’s story is a reminder that sometimes, a walk in the park can lead to an unexpected glimmer of gold — or, in this case, diamond.
If you’re feeling lucky, you can visit Crater of Diamonds State Park year-round. Who knows? You might walk away with more than just a souvenir.