In 2015, David Hole was prospecting in Maryborough Regional Park near Melbourne, Australia.
Armed with a metal detector, he discovered something unusual: a very heavy, reddish rock lying in yellow clay.
He took it home and tried everything to open it, sure there was a nugget in the rock – after all, Maryborough is in the Goldfields region, where Australia’s gold rush peaked in the 1800s.
To crack open his find, Hole tried a masonry saw, an angle grinder, a drill, and even dipped the contraption in acid. But even a sledgehammer couldn’t make a crack. That’s because what he tried so hard to open wasn’t a nugget.
As he discovered years later, it was a rare meteorite.
“It had a sculpted appearance with dimples,” geologist Dermot Henry of the Melbourne Museum told me The Sydney Morning Herald in 2019.
“That’s formed when they pass through the atmosphere. They melt on the outside and the atmosphere sculpts them.”
Unable to open the ‘rock’ but still intrigued, Hole took the nugget to the Melbourne Museum for identification.
“I’ve looked at a lot of rocks that people think are meteorites,” Henry told Channel 10 News.
In fact, after working at the museum for 37 years, examining thousands of rocks, Henry said only two of the offerings ever turned out to be actual meteorites.
This was one of two.
“If you saw a stone like that on Earth and you picked it up, it shouldn’t be that heavy,” explains Melbourne Museum geologist Bill Birch. The Sydney Morning Herald.
The researchers published a scientific paper describing the 4.6 billion-year-old meteorite, which they named Maryborough after the town near where it was found.
It weighs a whopping 17 kilograms (37.5 pounds), and after using a diamond saw to cut off a small piece, the researchers found that the compound contained a high percentage of iron, making it a common H5 chondrite .
Once opened, you can also see the tiny crystallized droplets of metallic minerals all over the place called chondrules.
“Meteorites provide the cheapest form of space exploration. They take us back in time and provide clues about the age, formation and chemistry of our solar system (including Earth),” said Henry.
“Some offer glimpses into our planet’s deep interior. In some meteorites, there is ‘stardust’ even older than our solar system, showing us how stars form and evolve to create elements of the periodic table.
“Other rare meteorites contain organic molecules such as amino acids, the building blocks of life.”
Although the researchers do not yet know where the meteorite came from and how long it has been on Earth, they do have a suspicion.
Our solar system was once a spinning pile of dust and chondrite rocks. Eventually, gravity pulled much of this material together into planets, but the remnants mostly ended up in a huge asteroid belt.
“This particular meteorite most likely comes from the asteroid belt between Mars and Jupiter, and was pushed out of there by some asteroids colliding with each other, and one day it will crash into Earth,” Henry told Channel 10 News.
Carbon dating suggests the meteorite may have been on Earth between 100 and 1,000 years, and there have been a number of meteor sightings between 1889 and 1951 that may correspond to its arrival on our planet.
The researchers claim that the Maryborough meteorite is much rarer than gold, making it much more valuable to science. It is one of only 17 meteorites ever recorded in the Australian state of Victoria, and is the second largest chondritic mass after a massive 55-kilogram specimen identified in 2003.
“This is only the 17th meteorite to have been found in Victoria, while thousands of gold nuggets have been found,” Henry told Channel 10 News.
“If you look at the sequence of events, it’s quite, you could say, astronomical that it’s being discovered at all.”
It’s not even the first meteorite to take a few years to reach a museum. In a particularly amazing story ScienceAlert covered in 2018, one space rock took 80 years, two owners, and a stint as a doorstop before it was finally revealed for what it really was.
Now is probably a good time to check your backyard for particularly heavy and hard-to-break rocks – you may be sitting on a metaphorical goldmine.
The study is published in Proceedings of the Royal Society of Victoria.
A version of this article was originally published in July 2019.