David Hall was prospecting in Maryborough Provincial Park near Melbourne, Australia in 2015. He discovered something unusual using a metal detector: a very heavy, red rock, embedded in yellow clay. He took it to his home and tried to open it in every way, certain that there was a gold nugget inside. Maryborough is located in the goldfields region, where the Australian gold rush reached its peak in the nineteenth century.
Hall used a rock saw, angle grinder, and a drill, and even doused it with acid to open it. Not even a heavy hammer could make a crack, because what he was trying so hard to open was not a golden nugget, as he discovered years later, it was a rare meteorite.
“It had a chiseled, dimpled appearance,” Dermot Henry, a geologist at the Melbourne Museum, told the Sydney Morning Herald in 2019. This appearance is formed as it passes through the atmosphere. “It melts from the outside, and the atmosphere sculpts it.”
Hall was unable to open the “rock,” but remained fascinated by it, so he took the piece to the Melbourne Museum for identification. “I’ve looked at a lot of rocks that people think are meteorites,” Henry told Channel 10 News. Henry said only two of the offerings turned out to be real meteorites after 37 years of working at the museum and examining thousands of rocks. This was one of the two.
“If you saw a rock like that on the ground, and you picked it up, it shouldn’t be that heavy,” Bill Birch, a geologist at the Melbourne Museum, 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 discovered. It weighs 17 kilograms, and after using a diamond saw to cut off a small slice of it, researchers discovered that its composition contains a high percentage of iron, making it an ordinary H5 chondrite. You can also see tiny crystalline droplets of metallic minerals throughout it once you open it, called chondrules.
“Meteorites are the cheapest way to explore space,” Henry said. “They take us back in time, providing clues to the age, composition and chemistry of our solar system, including Earth. Some of them offer a peek into the interior of our planet. Some meteorites contain “stardust” even older than our solar system, showing us how stars form and evolve to form the elements of the periodic table. “Other rare meteorites contain organic molecules such as amino acids, which are the building blocks of life.”
Researchers have some guesses, although they don’t yet know where the meteorite came from and how long it has been on Earth.
Our solar system was once a spinning pile of dust and chondrite rocks. Gravity collected much of this material to form planets, but the remains mostly settled in a massive asteroid belt.
“This particular meteorite likely came out of the asteroid belt between Mars and Jupiter, was propelled by some asteroids colliding with each other, and then one day collided with Earth,” Henry told Channel 10 News. Carbon dating suggests that the meteorite was on Earth between 100 and 1,000 years ago, and several sightings were recorded between 1889 and 1951, which may indicate its arrival on our planet.
Researchers argue that the Maryborough meteorite is much rarer than gold, making it more valuable to science. It is one of only 17 meteorites recorded in the Australian state of Victoria, and is the second largest chondrite mass, after a massive 55-kilogram specimen discovered in 2003. “This is only 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 can be said to be an astronomical discovery.”
It’s not the first meteorite to take a few years to reach a museum. It took a single space rock 80 years, two owners, and an intervening period before it was finally revealed for what it was in a stunning story covered by Science Alert in 2018.
Only a few meteorites that land on Earth are closely related to their parent body in space. But in 2024, three newly published papers give us compelling origin stories for more than 90% of today’s meteorites. Now might be a good time to check your backyard for rocks that are too heavy to break, perhaps sitting on a metaphorical gold mine.
