In 2015, David Hole was conducting exploration in the Maryborough Regional Park near Melbourne, Australia.

With a metal detector, he found something unusual-a very heavy red rock placed in some yellow clay.

He took it home, tried every means to open it, and made sure that there was a gold nugget in the rock—after all, Maryborough was located in the gold mining area, where the Australian gold rush peaked in the 19th century.

To unlock his findings, Hall tried a rock saw, angle grinder, drill bit, and even soaked it in acid. However, even the sledgehammer could not be hit. That's because he desperately wanted to open it, not a gold nugget. Many years later he discovered that this was a rare meteorite.

Dermot Henry, a geologist at the Melbourne Museum, told the Sydney Morning Herald: “It has this carved, dented appearance.”

"This is formed when they pass through the atmosphere, they melt outside, and the atmosphere shapes them."

Unable to open the "Rock", but still curious, Hall took the gold nugget to the Melbourne Museum for identification.

"I have seen a lot of rocks that people think are meteorites," Henry told Channel 10 News.

In fact, after 37 years of working in the museum and examining thousands of rocks, Henry explained that only two of them were real meteorites.

This is one of the two.

Another geologist at the Melbourne Museum, Bill Birch, told the Sydney Morning Herald in 2019: “If you see a rock like this on the earth and pick it up, it shouldn’t be that heavy. ."

Researchers published a scientific paper describing this 4.6 billion-year-old meteorite, which they called Maryborough after the name of the town near the site of discovery.

This is a huge 17 kg (37.5 lb). After cutting a small piece with a diamond saw, they found that the composition has a high iron content, making it an H5 ordinary chondrite.

After opening, you can also see tiny droplets of metallic mineral crystals, called spherulites.

"Meteorites provide the cheapest form of space exploration. They bring us back in time and provide 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. Among some meteorites, there are'stardust' older than our solar system, which shows us how stars form and evolve to create the elements of the periodic table.

"Other rare meteorites contain organic molecules, such as amino acids; they are the building blocks of life."

Although the researchers don't yet know where the meteorite came from and how long it may have been on Earth, they do have some speculations.

Our solar system used to be a rotating pile of dust and chondrites. Eventually, gravity gathered a large amount of this material into the planet, but most of the rest ended up in a huge asteroid belt.

"This particular meteorite is likely from the asteroid belt between Mars and Jupiter. It was pushed away by some asteroids colliding with each other, and then one day it hit the earth," Henry told Channel 10 News.

Carbon dating shows that this meteorite has existed on Earth for 100 to 1000 years, and that many meteors appeared between 1889 and 1951, which may correspond to the time it reached our planet.

Researchers believe that the Maryborough meteorite is much rarer than gold and therefore more valuable to science. It is one of only 17 meteorites in the history of Victoria, Australia, and the second largest chondrite after the 55 kg giant meteorite discovered in 2003. 

"This is only the 17th meteorite found in Victoria, and thousands of gold nuggets have been discovered," Henry told Channel 10 News.

"Looking at this series of events, you might say that it was found to be totally astronomical."

It is not even the first meteorite that takes several years to enter the museum. In a particularly surprising story reported by ScienceAlert in 2018, a space rock took 80 years, two owners, and acted as a doorstop before it was finally revealed.

Now may be a good time to check your backyard for particularly heavy and unbreakable rocks-you may be sitting on a metaphorical gold mine.

The research was published in the Proceedings of the Royal Society of Victoria.

A version of this article was originally published in July 2019.