Miranda Hollingshead was hot and tired during an extended family outing to Crater of Diamonds State Park in Arkansas, a couple of hours away from her Bogata, Texas, home. Her two young kids were over it. There was dirt everywhere, but no gemstones in sight.

So as others in her group continued the dusty hunt on August 16, she found shade and did what comes naturally to 20-somethings who need guidance: turned to YouTube.

"I searched 'Crater of Diamonds how to find a diamond,'" Hollingshead, 27, said in an interview Friday. "That's all I wanted to know - how do I find diamonds here?" The park in Murfreesboro, Arkansas, is known for the 40 kinds of rocks and minerals visitors can hunt for and take home.

As Hollingshead watched the first video, featuring an "older gentleman" talking about dry-sifting techniques, she ran her hands through the rocks on the ground. She felt something pop over her finger and looked down to see what it was.

"I was like, 'Oh, that's shiny,'" she says. Then she realised: "Oh, my God, that's a diamond."

A check by experts at the park confirmed her hunch: It was a 3.72-carat yellow diamond, the largest diamond registered at the park since a teen found a 7.44-carat brown diamond in 2017. Hollingshead's is the largest yellow diamond found since October of 2013.

Park interpreter Waymon Cox said visitors discover an average of one or two diamonds a day, most around a quarter of a carat in size. A 37.5-acre search field is actually the eroded surface of a volcanic crater, according to the Crater of Diamonds website. So far this year, 319 diamonds have been registered at the park, with 13 weighing at least one carat, a news release said. Yellow diamonds are the least common to discover at the park, followed by brown and white.

Cox said many visitors consult how-to videos before or during their searches. But he's not aware of a find quite as serendipitous as the one Hollingshead made.

"I haven't heard of that one too often, of somebody watching a video and looking down and finding one," he said. "That was pretty funny."

Hollingshead was asked to name the diamond, which is roughly the size of a pencil eraser. With input from her son and mother, and a nod to her superhero fandom, she called it the Caro Avenger. Then she took it for additional verification. One expert said they did not believe it was actually a diamond, but three more who examined it assured her that the original diamond certification from the park was correct.

She hasn't had the stone appraised, and she hasn't decided what to do with it yet. But she's leaning toward taking her mom's advice and getting it cut into two separate diamonds to pass on to her daughter and son, who are now 3 and 4.

"I mean, anyone can use the money, but not everyone can tell their kids, 'Hey, that ring you're about to give to whoever you're going to get engaged to, or the ring you got engaged with, your mom found that,'" she says. "That way it carries on, it's just a family heirloom at that point."