Minnesota man finds 3.81-carat brown diamond at Arkansas's Crater of Diamonds State Park

David DeCook found a 3.81-carat diamond at Arkansas’s Crater of Diamonds State Park, the largest discovered there this year.

Credit: Arkansas State Parks

David DeCook shows off his 3.81-carat brown diamond that he found at Arkansas’s Crater of Diamonds State Park on April 21.

MURFREESBORO, Ark. — A Minnesota man, who is a frequent visitor to Arkansas’s Crater of Diamonds State Park, spotted a 3.81-carat brown diamond on April 21. According to an Arkansas State Parks press release, it is the largest diamond to be registered this year.

David DeCook visited the park with his family last Monday. He and his brother, Derek, have registered several diamonds over the years, but the press release said this is the largest one either has found.

About an hour into exploring the park’s plowed diamond search area, he reportedly made his way down a hill south of the park’s south wash pavilion, where he spotted the diamond. The press release said he first thought it was a candy wrapper, but after inspecting further, he knew what he had found.

In true sibling-rivalry fashion, he called his brother over and said, “Oh, you’re going to be mad once you see what I found!”

DeCook returned to the park a few days later to register the diamond. Park staff determined that it was a 3.81-carat diamond. It has a metallic, copper luster in a blocky, triangular shape, according to Arkansas State Parks.

Those who find diamonds tend to name their discoveries, and DeCook landed on naming his the Duke Diamond after his dog. He told Arkansas State Parks that he’s not sure what he will do with his diamond.

Park officials said the Duke Diamond is the largest one found at the Crater of Diamonds Park since January 2024, when French visitor Julien Navas found the 7.46-carat Carine Diamond.

The day before DeCook visited the park, there was nearly an inch of rain. The park saw more than 12 inches of rain during April. Assistant Park Superintendent Waymon Cox said these kinds of conditions increase surface finds like DeCook’s.

“Many of the park’s largest diamonds are found on top of the ground. As rain falls in the search area, it washes away the dirt and uncovers heavy rocks, minerals, and diamonds near the surface,” Cox said.

As of May 1, 2025, park staff have registered 220 diamonds, officials said. DeCook’s diamond was the 217th registered at Crater of Diamonds this year.