A man guards a rock for years, hoping it is gold. It turns out to be much more valuable: ScienceAlert

In 2015, David Hole researched 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, certain that there was a nugget of gold in the rock – after all, Maryborough is in the Goldfields region, where the Australian gold rush reached its peak in the 19th century.

To break up his find, Hole tried a rock saw, an angle grinder, a drill, even dousing the thing with acid. However, even a hammer could not make a crack. This is because what he was trying so hard to open was not a nugget of gold.

As he found out years later, it was a rare meteorite.

“It had this sculpted, dimpled look,” Melbourne Museum geologist Dermot Henry said The Sydney Morning Herald in 2019

“This forms when they go 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 been looking at a lot of rocks that people think are meteorites,” Henry told Channel 10 News.

In fact, after 37 years working at the museum and examining thousands of rocks, Henry said only two of the offerings have turned out to be actual meteorites.

It was one of the two.

The Maryborough meteorite with a slab cut from the table. (Melbourne Museum)

“If you saw a rock on Earth like this and picked it up, it shouldn’t be that heavy,” 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 which it was found.

It weighs a whopping 17 kilograms (37.5 pounds), and after using a diamond saw to cut a small slice, researchers discovered that it has a high percentage of iron, making it H5 ordinary chondrite.

Once opened, you can also see the tiny crystallized droplets of metallic minerals all over it, the so-called chondrules.

“Meteorites provide the cheapest form of space exploration. They take us back in time, providing clues about the age, formation and chemistry of our Solar System (including Earth).” Henry said.

“Some provide a glimpse into the deep interior of our planet. Some meteorites contain “stardust” even older than our solar system, showing us how stars formed and evolved to create 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. (Burch et al., PRSV, 2019)

Although researchers still don’t know where the meteorite came from or how long it may have been on Earth, they have some guesses.

Our Solar System was once a swirling pile of dust and chondrite rock. Gravity eventually gathered much of this material together into planets, but the remnants mostly ended up in a huge an asteroid belt.

“This particular meteorite most likely exited the asteroid belt between Mars and Jupiterand it was pushed out of there by some asteroids crashing into each other, then one day it crashes into Earth,” Henry told Channel 10 News.

Carbon dating suggests that the meteorite was on Earth between 100 and 1,000 years ago, and there were a number of meteor sightings between 1889 and 1951 that could be consistent with its arrival on our planet.

Researchers say 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 chondrite mass after a massive 55kg specimen 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, you could say it’s pretty astronomical that it was discovered at all.”

This isn’t even the first meteorite to take several years to reach a museum. In a particularly amazing story ScienceAlert reported in 2018, a space rock took 80 years, two owners and a layover before it was finally revealed for what it really was.

Now is probably as good a time as any to check your backyard for particularly heavy and hard-to-break rocks—you might 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.