Chad Johnson has found about 80 diamonds at Crater of Diamonds State Park since moving to Murfreesboro in February, but the former Iowa resident on Monday nearly threw away his largest find yet. A cube-shaped rock plucked out of his sifters turned out to be a 4.38-carat, tea-colored diamond.

"Every time someone finds a big diamond here at the park, they just get slammed with tourists," said Johnson, 36, a park regular. "This has already been a bad summer for tourists and they were looking forward to winding down and then this happened."

Johnson made the dig Saturday at the park, and left his equipment in a locker. When he came back Monday morning, he made the discovery.

Since moving to Arkansas, Johnson said he had gotten by selling the diamonds he found at the park. He only recently took a job at a local convenience store partly because he "got tired of selling diamonds to make ends meet."

Crater of Diamonds State Park, which opened in 1972, is the world's only diamond-producing site open to the public. Visitors can keep the gems they unearth. The largest diamond found at the park was the 16.37-carat Amarillo Starlight, a white diamond found by a Texas visitor in 1975.

Johnson's find is the second-largest diamond uncovered at the park this year. In June, a Louisiana man found a 4.8-carat diamond.

Overall, more than 700 diamonds have been found at the park this year.

Park officials declined to speculate how much money Johnson could raise from selling the diamond. Johnson suggested he expects much more than what he is used to getting.

"If someone offers me that much money, it's theirs," Johnson said.

But Johnson acknowledged he was relishing the find — and looked forward to making more.

"I can finish out the day even," Johnson said.