Man keeps rock for years, hoping it’s gold. It turns out to be much more valuable: ScienceAlert

In 2015, David Hole was exploring in 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 went out of his way to open it, sure there was a gold nugget inside the rock – after all, Maryborough is in the Goldfields region, where Australia’s gold rush peaked in the 19th century .

To crack his discovery, Hole tried a rock saw, an angle grinder, a drill, even dousing it with acid. However, not even a sledgehammer could make a crack. That’s because what she was trying so hard to open wasn’t a gold nugget.

As he discovered years later, it was a rare meteorite.

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

“They’re formed when they pass through the atmosphere. They’re melting out and the atmosphere is carving 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.

Indeed, after 37 years of working at the museum and examining thousands of rocks, Henry said only two of the offerings had ever turned out to be true meteorites.

This was one of two.

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

“If you’ve seen a rock on Earth like this and picked it up, it shouldn’t be that heavy,” explained Melbourne Museum geologist Bill Birch. The Sydney Morning Herald.

The 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 a whopping 17 kilograms (37.5 pounds), and after using a diamond saw to cut a small slice, the researchers found that its composition had a high percentage of iron, making it an ordinary H5 chondrite.

Once you open it, you can also see the tiny crystallized droplets of metallic minerals inside it, called chondrules.

“Meteorites provide the cheapest form of space exploration. They transport 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 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 table elements periodic.

“Other rare meteorites contain organic molecules such as amino acids, the building blocks of life.”

close-up of the Maryborough meteoriteA slab cut from the Maryborough meteorite. (Birch et al., PRSV, 2019)

While researchers don’t yet know where the meteorite came from and how long it may have stayed on Earth, they do have some guesses.

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

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

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

Researchers argue 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 whopping 55-kilogram specimen identified in 2003.

“This is only the 17th meteorite found in Victoria as 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 also not the first meteorite to take a few years to make it to a museum. In one particularly startling story covered by ScienceAlert in 2018, a space rock took 80 years, two owners, and a stint as a doorstop before finally being revealed for what it really was.

Now is probably the best time to check your garden for rocks that are particularly heavy and hard to break – 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.

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