A California woman made a surprise find after discovering a 4.38 carat yellow diamond in Arkansas’ Hot Springs National Park.

Noreen Wredberg was visiting the park with her husband Michael and decided to explore the Crater of Diamonds park, the state Parks Department told NBC News.

“I first saw the park featured on a TV show several years ago,” Ms Wredberg told the department.

“When I realised we weren’t too far away, I knew we had to come.”

The couple arrived at the park after several days of rain which had left the slightly-dry soil in an ideal condition for finding diamonds.

Image: The State Parks of Arkansas

Ms Wredberg had been searching for about an hour before she noticed the large gem.

“I didn’t know it was a diamond then, but it was clean and shiny, so I picked it up!” she said, according to NBC News.

If visitors find diamonds at the park, they can take it to the park’s Diamond Discovery Centre to confirm whether the diamond is real.

Arkansas is the only state with a public diamond mine, with more than 75,000 unearthed at the Crater of Diamonds since 1906.

The Arkansas parks department said the diamond Ms Wredberg found is the biggest in the last year.

Ms Wredberg has been allowed to keep the stone, but said she was unsure about what she would do with it.

Image: The State Parks of Arkansas / Facebook

This article first appeared on Over60.