The diamond Fox found is "about the size an English pea," park retail specialist Amanda Johnson told OzarksFirst.
“It contains a few inclusions, like most diamonds from the park, but it also has an unmistakable sparkling, metallic shine,” she said.
Fox and his wife live in Joliet, Montana, but both are Arkansas natives. He said they were walking around the park grounds “looking for a glimmer” when he noticed the diamond.
"I was surface looking, walking very slowly and looking very slowly and I saw it," Fox told ABC News. "I got down for a closer inspection because I wasn't quite sure what to look for, but as soon as I saw it I thought, 'that's probably a diamond.'"
When Fox showed the gem to the employees at the park’s Diamond Discovery Center, "one of the ladies sort of gasped and I just saw this big smile," he said.
"We still can't believe that we found it. It was just by the grace of God and love," Fox told ABC News.