The tourist, Brandon Kalenda of Maurepas, La., visited the Crater of Diamonds State Park in Murfreesboro, Ark., last week after his girlfriend's mother watched the Duggar family visit the park in a show episode and decided her family should do the same.
Kalenda, joined by girlfriend Jodee, son Jaxson and five other family members, stopped at the park March on the way to a family reunion in Minnesota. After 20 minutes of searching, Kalenda found the diamond, but he didn't even realize the treasure he had found.
"I thought it was broken glass," Kalenda, 20, said of the pea-sized diamond he spotted in a pocket of a rock. "I showed a family member and he said maybe I should have someone check it out.
"I showed the park employees and they were speechless," Kalenda told GoodMorningAmerica.com. "That's how I found out it was a diamond."
Kalenda, a construction worker who had never hunted for diamonds before, was given a small container by park officials to hold the diamond. He says he hasn't removed it from his pocket since.
Once he returns home from Minnesota, Kalenda says he is going to spend some time deciding what to do with the diamond he has named "Jax," after his infant son.
"I'm thinking about keeping it and putting it into a ring," he said, adding that the diamond has been estimated to be worth as much as $20,000.
"It's hard to believe something like that," Kalenda said. "I'm definitely still in shock."