A man thought he found a piece of glass in an Arkansas state park. It was a 9.07-carat diamond.

A man discovered a 9.07-carat diamond at a state park in southwestern Arkansas after thinking the precious gem was a piece of glass. Kevin Kinard of Maumelle found the second-largest diamond in the 48-year history of Crater of Diamonds State Park on Labor Day, according to a news release from Arkansas State Parks.

Kinard, a bank manager, said he and his friends hauled sifting equipment to the state park in Murfreesboro. Kinard noted that he's been visiting Crater of Diamonds regularly since he was a kid but had never stumbled upon a diamond until Sept. 7.

"I only wet sifted for about ten minutes before I started walking up and down the plowed rows," he said. "Anything that looked like a crystal, I picked it up and put it in my bag."

While searching in the southeast portion of the 37.5-acre diamond search area, Kinard scooped up a marble-sized crystal that had a rounded, dimpled shape.

"It kind of looked interesting and shiny, so I put it in my bag and kept searching," Kinard said. "I just thought it might've been glass."

Several hours later, Kinard said he and his comrades stopped by the park's Diamond Discovery Center, where park workers identify visitor findings and register diamonds.

"I almost didn't have them check my finds, because I didn't think I had found anything," Kinard said. "My friend had hers checked, though, so I went ahead and had them check mine, too."

Upon having his finds assessed, an employee informed Kinard he had discovered a diamond.

"I honestly teared up when they told me," Kinard said. "I was in complete shock!"

Ginger Burton, Kinard's friend who was with him, posted a congratulatory message on Facebook, noting she had kept the news secret for nearly three weeks.

Assistant Superintendent Dru Edmonds noted that conditions were ideal for Kinard to spot the gem.

"Park staff plowed the search area on August 20, just a few days before Tropical Storm Laura dropped more than two inches of rain in the park," he said. "The sun was out when Mr. Kinard visited, and he walked just the right path to notice the sunlight reflecting off his diamond."

As of Wednesday, 246 diamonds have been registered at Crater of Diamonds State Park this year, weighing a total of 59.25 carats. On average, people find one or two diamonds there daily.

Last year, a schoolteacher from Nebraska found a 2.12. carat diamond when he visited the park.