In 2015, David Hall was excavating in Maryborough Provincial Park near Melbourne, Australia.
Armed with a metal detector, he discovers something unfamiliar – a very heavy reddish rock resting in some yellow clay.
He took it home and tried everything to open it up, making sure there was a gold nugget inside the rock – after all, Maryborough is in the Goldfields region, where the Australian gold rush peaked in the 19th century.
To crack his discovery, Hall experimented with a rock saw, angle grinder, drill, and even dipped the object in acid. However, not even a sledgehammer could make a crack. This was because what he was trying so hard to open was not a gold nugget.
As it was discovered years later, it was a rare meteorite.
Dermot Henry, a geologist at the Melbourne Museum, “had this sculpted, submerged look” Tell Sydney Morning Herald in 2019.
“This is formed when it comes through the atmosphere, it’s melting from the outside, and the atmosphere is sculpting it.”
Unable to open the “rock”, but still intrigued, Hall 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.
Indeed, after 37 years working in the museum and examining thousands of rocks, Henry said that only two of the exhibits turned out to be real meteorites.
This was one of the two.
Maryborough meteorite cut from the block. (Melbourne Museum)
“If you see a rock on the ground like this, and pick it up, it shouldn’t be very heavy,” Melbourne Museum geologist Bill Birch, explained to Sydney Morning Herald.
Researchers have 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 17 kilograms (37.5 pounds), and after using a diamond saw to cut a small slice, researchers discovered that its composition has a high iron content, making it H5 normal chondrite.
Once opened, you can also see the tiny crystalline droplets of metallic minerals found throughout it, which are called chondrocytes;.
“Meteorites provide the cheapest form of space exploration. They transport us back in time, providing clues to the age, formation, and chemistry of our solar system (including Earth),” Henry said.
Some provide a glimpse into the depths of our planet’s interior. In some meteorites, there is ‘stardust’ older than our solar system, showing us how stars form and evolve to create the elements of the periodic table.
“Other rare meteorites contain organic molecules such as amino acids; the building blocks of life.”
Slab cut from the Maryborough meteorite. (Birch et al., PRSV, 2019)
Although researchers do not yet know where the meteorite came from and how long it has been on Earth, they do have some guesses.
Our solar system was once a spinning mound of dust and chondrite rock. Eventually, gravity brought much of this material together to form planets, but most of the leftovers ended up in bulky form asteroid Belt.
“This particular meteorite most likely comes from the asteroid belt in between Mars And the Jupiter“It was pushed out by some asteroids that slammed into each other, and then one day it hit Earth,” Henry told Channel 10 News.
Carbon dating indicates that the meteorite was on Earth between 100 and 1000 years old, and there were a number of meteor sightings between 1889 and 1951 that could correspond to its arrival on our planet.
Researchers argue that the Maryborough meteorite is much rarer than gold, which makes it much more valuable to science. It is one of only 17 meteorites ever recorded in the Australian state of Victoria, and it is the second-largest cartilaginous massif, after a massive 55-kilogram specimen identified in 2003.
“This is the 17th meteorite found in Victoria, while thousands of gold nuggets have been found,” Henry told Channel 10 News.
“Given the chain of events, it could be said, it is astronomical that it was discovered at all.”
It’s not the first meteorite to take a few years to get to a museum. In a particularly amazing story covered at ScienceAlert in 2018, it took one space rock 80 years, two owners, and a detour before it was finally revealed for what it was.
It’s probably as good a time as any to check your backyard for rocks that are heavy and hard to break – you might be sitting on a metaphorical gold mine.
The study has been published in Proceedings of the Royal Society of Victoria.
A version of this article was originally published in July 2019.