A teenager made the discovery of a lifetime when he stumbled across a 7.44 carat diamond at an Arkansas state park.

Officials at Crater of Diamonds State Park at Murfreesboro say the rock found Saturday by 14-year-old Kalel Langford is the seventh largest found since the park was established in 1972. The park hasn't provided an estimate of the diamond's value.

“It was just a few inches from a stream of water, with a bunch of other rocks that were about the same size,” Langford said.

He has named it "Superman's Diamond" and plans to keep it as a souvenir of his visit.

Craig Langford, Kalel's father, said they were only at the park for 30 minutes when his son made the discovery.

"Its color was so dark that we weren't sure if it was a diamond but we knew we needed to have it looked at," said Craig.

Park interpreter Waymon Cox describes the diamond as pinto-bean sized and similar in color to coffee.

“This diamond is a truly extraordinary find,” Cox said. “It was Kalel’s dream to visit the Crater of Diamonds State Park, and now he will always be part of this park’s remarkable history.”

The largest diamond ever discovered in the United States, the 40.23 carat "Uncle Sam," was unearthed on the land in 1924.

The Associated Press contributed to this report.