David DeCook, a Minnesotan who frequents the Arkansas park, found the 3.81-carat stone on a family visit to the site on Apr. 21.
Murfreesboro, Ark.—Late last month, a frequent out-of-state visitor uncovered a nearly 4-carat diamond at the Crater of Diamonds State Park in Murfreesboro, Arkansas.
David DeCook from Stewartville, Minnesota, discovered a 3.81-carat brown diamond while visiting the park with his family on Apr. 21. He named it “The Duke Diamond,” after his dog.
White, brown, and yellow diamonds are the most common colors of diamonds found at the park, in that order, the park said.
Featuring a metallic, copper luster and a blocky, triangular shape, the park said The Duke Diamond is the largest diamond registered so far this year.
The 3.81-carat Duke Diamond next to a quarter
The Crater of Diamonds State Park is North America's only public diamond mine, maintaining a "finders, keepers” policy for visitors who come to scour the 37.5-acre plowed diamond search area.
DeCook made his find about an hour after entering the field, spotting it “almost immediately” after heading down a hill south of the park’s south wash pavilion.
He told the park he thought it was a candy wrapper at first, but knew once he saw “a metallic, tinfoil-like shine,” he’d found a diamond.
After taking a closer look at the gem, he called to his brother Derek, “Oh, you’re going to be mad once you see what I found!”
David DeCook with the Duke Diamond
The brothers have been regular visitors to Crater of Diamonds State Park for years and both have registered numerous diamonds. The Duke Diamond, however, is the largest diamond either has found, so far.
DeCook pocketed the stone and returned to the park a few days later for park staff to identify and register the diamond and name it.
He said he isn’t sure what he will do with his diamond.
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The Duke Diamond is the largest diamond found at the park since French visitor Julien Navas discovered the 7.46-carat “Carine Diamond” in January 2024, according to the park.
It is the 217th diamond registered at the park in 2025.
The day before DeCook’s visit, the park received nearly an inch of rain. Rainfall causes erosion in the search area, the park said, and often leads to an increase in surface finds.
“April has been a very wet month at the park, with more than 12 inches of rain,” said Assistant Park Superintendent Waymon Cox.
“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.”
The park said 220 diamonds have been registered so far in 2025, weighing more than 32 carats total.
The Crater of Diamonds became an Arkansas State Park in 1972.
More than 75,000 diamonds total have been unearthed at the site since 1906, when the previous landowner, farmer John Huddleston, first discovered diamonds in the area.
One of the park’s most well-known diamonds is the Strawn-Wagner, a 3.03-carat white diamond found in 1990 by Murfreesboro resident Shirley Strawn. It was later cut into a 1.09-carat round brilliant shape graded as ideal cut, D-colorless, and flawless, and set in a platinum and 24-karat gold ring.
In 1998, the state of Arkansas purchased the stone for $34,700 in donations and placed it on permanent display at the park visitor center.
The park also produced “Uncle Sam,” the largest diamond ever discovered in the country. The 40.23-carat white diamond with a pink cast was unearthed during an early mining operation in 1924.
