In 2015, David Hole was surveying in the Maryborough Regional Park near Melbourne, Australia.
Armed with a metal detector, he discovered something out of the ordinary: a very heavy reddish rock resting on yellow clay.
He took it home and tried everything to open it, sure that there was a nugget of gold inside the rock; after all, Maryborough is in the Goldfields region, where the Australian gold rush peaked in the 19th century.
To open up his find, Hole tried a rock saw, an angle grinder, a drill, and even sprayed the thing with acid. However, not even a sledgehammer could make a crack. That’s because what he was trying so hard to open was not a gold nugget.
As he discovered years later, it was a rare meteorite.
“It had this sculpted, dimpled look,” said Melbourne Museum geologist Dermot Henry. saying The Sydney Morning Herald in 2019.
“That’s formed when they go through the atmosphere, 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 37 years of working at the museum and examining thousands of rocks, Henry said only two of the offerings turned out to be actual meteorites.
This was one of the two.
The Maryborough meteorite, with a slab cut from the mass. (Melbourne Museum)
“If you saw a rock on Earth like this and picked it up, it shouldn’t be that heavy,” said Melbourne Museum geologist Bill Birch, explained to 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 a small slice, the researchers discovered that its composition had a high percentage of iron, making it a ordinary chondrite H5.
Once open, you can also see the tiny crystallized droplets of metallic minerals that run through it, called chondrules.
“Meteors provide the cheapest form of space exploration. They transport us back in time and provide clues to the age, formation, and chemistry of our Solar System (including Earth).” Henry said.
“Some allow glimpses into the deep interior of our planet. In some meteorites, there is ‘stardust’ even older than our Solar System, showing us how stars form and evolve to create elements on the periodic table.
“Other rare meteorites contain organic molecules like amino acids, the building blocks of life.”
A slab cut from the Maryborough meteorite. (Birch et al., PRSV, 2019)
Although researchers don’t yet know where the meteorite came from and how long it may have been on Earth, they have some guesses.
Our Solar System was once a spinning pile of chondrite rocks and dust. Gravity eventually packed a lot of this material into planets, but most of the remains ended up in a huge asteroid belt.
“This particular meteorite most likely comes out of the asteroid belt between Mars Y Jupiterand it’s been pushed out of there by some asteroids that hit each other, and one day it hits Earth,” Henry told Channel 10 News.
Carbon dating suggests that the meteorite has been on Earth between 100 and 1,000 years, and there have been several meteorite sightings between 1889 and 1951 that could correspond to its arrival on our planet.
The researchers argue that the Maryborough meteorite is much rarer than gold, making it much more valuable to science. It is one of 17 meteorites ever recorded in the Australian state of Victoria, and is the second largest chondritic mass, after a massive 55-kilogram sample identified in 2003.
“This is only the 17th meteorite found in Victoria, while thousands of gold nuggets have been found,” Henry told Channel 10 News.
“Looking at the chain of events, it’s quite, one might say, astronomical that it was discovered.”
It’s not even the first meteorite to take a few years to make it to a museum. In a particularly amazing story. ScienceAlert covered in 2018, a space rock took 80 years, two owners, and a season as a doorstop before finally being revealed for what it really was.
Now is probably a good time to check your backyard for particularly heavy, hard-to-break rocks—you could be sitting on a metaphorical gold mine.
The study was published in Proceedings of the Royal Society of Victoria.
A version of this article was originally published in July 2019.
