After an hour of energetic digging in the hot sun, Kaleb has collected a decent number of rocks and he's hopeful some will reveal a hidden treasure.
This is the primary school student's first time fossicking for thunder eggs, but he knows what he's looking for.
"You know it's a thunder egg because it will have this sort of bubbly thing on it," Kaleb says.
He is one of scores of children who have spent the school holidays fossicking for gemstones and thunder eggs in central Queensland.
Soon it is time for the moment of truth.
A short distance from the digging site, Don Kayes takes the small, round rock and carefully cuts it open with a diamond saw.
The sound is deafening, but as the rock falls in half, the intricate patterns in maroon and dark blue are revealed.
"You've found some good ones," Mr Kayes tells Kaleb.
"Look, this one has a piece of agate," he points out.
Mr Kayes runs a thunder egg and gemstone fossicking park at Mt Hay, 30 minutes' drive west of Rockhampton, and the reaction on Kaleb's face is the reason he's been doing this for decades.
"That's enough, isn't it?"
Exploring close to home
Since the COVID-19 pandemic, most visitors have been locals exploring their own backyard.
"The past two years, especially the school holidays, I don't think I have ever seen it as busy," Mr Kayes says.
Many are return visitors who have brought their children and are now bringing their grandchildren.
"The family I just cut for, he came here about 32 years ago when he was a kid, and here he is, bringing his child to fossick today."
What are thunder eggs?
Although thunder eggs are found throughout Australia, Mt Hay has one of the country's largest deposits that formed 120 million years ago.
It's an odd name to give a rock, but it's thought to originate from a Native American legend that described thunder eggs as dropping from the sky during thunderstorms.
They are fascinating enough for the Australian Museum in Sydney to display hundreds of them — and the bulk are from Mt Hay, says Ross Pogson, who manages the collection.
Although there are deposits found in parts of NSW, Queensland had the right volcanic conditions hundreds of millions of years ago for thunder eggs to form.
They form in rhyolite, a slow-moving treacle-like lava, and water carrying silica seeps through cavities, leaving deposits.
"You get a star-shaped pattern in the middle and this can be filled with agate or sometimes with more coarsely crystalline materials like amethyst," Mr Pogson says.
Lucky dip
Thunder eggs may not be worth a lot in monetary value. The appeal is more in what they reveal.
"You can't tell what's inside a thunder egg by looking at it," Mr Pogson says.
"When you cut it open, there might be nothing or there might be a beautiful pattern of banded agate, or there might even be a hollow in the middle with beautiful crystals of clear quartz or amethyst."
For Mr Kayes, it never gets old.
"It's a surprise," he says.
"It's a lucky dip, that surprise package. It doesn't look much from the outside, a little bit of a rounded-looking rock, but what beauty can be within is quite amazing."
As for Kaleb, he was satisfied with his morning's work and quite surprised with the results.
"I was not expecting them to look as good as what they do."
