It was almost dinner-time and friends Paul and John, who had been out gold-fossicking near Georgetown, Queensland, were finishing up for the day.

 

As he wandered along to meet John, Paul's metal-detector suddenly started emitting a strong sound.

"I thought, 'gee, that was a good signal'," he said.

"And I couldn't get rid of it so I started scraping away and kept getting deeper and the signal got better."

Friends John and Paul had been fossicking for several days when they struck an unexpected sort of gold. (Supplied)

Paul called John and asked him to come and help. The pair dug for two hours until they eventually encountered the rock.

Covered in dirt, it did not look like anything special, but they knew it had to be unusual.

"We chipped the top of the rock and I thought, 'there's no rock here like that ... I don't know what we've got here'," Paul said.

"When we went to roll it out of the hole it was that heavy. We knew it was more than an ordinary stone.

"So we got it into the ute and it rolled around in the back of the ute for about four weeks."

When the pair finally got around to taking their find to Geoscience Australia to be examined, the reaction was instant.

"It's funny, we often get people [who] come and visit thinking they've found meteorites, and generally 99 times out of 100 it's not the case,"  National Mineral Fossil Collection curator Steven Petkovski said.

"We went out to the back of their car and opened up the boot and straight away I was very excited to see, this is indeed an iron meteorite and these guys have the real deal, the real McCoy."

How I wonder what you are

The very rare iron-nickel meteorite is believed to have come from the edge of the metal core of a former asteroid. (Supplied)

The romance of a shooting star seen from earth is far removed from the actual, violent event of a meteor burning up as it enters the atmosphere.

Most disintegrate upon entry, but some are big enough to survive the long journey to the ground and hit the earth's surface.

At this point, the meteors become meteorites.

John and Paul had been out that day looking for gold, but what they had actually stumbled upon was a very rare iron-nickel meteorite, which scientists believe may have come from the edge of the metal core of a former asteroid 4.5 billion years ago.

It is one of only six officially confirmed, named and classified in the world and the only one to have been found in Australia. Four of the others were found in Antarctica and the fifth is held in the USA.

The meteorite John and Paul found is also the largest of the six — weighing in at 24.3kg.

It took time to remove dirt from the meteorite, which spent four weeks in the back of a ute before being taken to Geoscience Australia. (Supplied)

"It's rare, and it's rare to find this type of meteorite," Mr Petkovski said.

He said the meteorite would assist researchers in understanding more about the solar system.

"Scientifically there's plenty of discovery and work that needs to be done on this, and that'll tell us a lot more about the building blocks of the solar system, planets, formations," he said. 

"Also due to the type of meteorite it is, a lot more about the mineralogy and chemistry of the solar system."

Visitors to Geoscience Australia in Canberra will also be able to view the ancient rock, which tells a fascinating story.

"The bronze coloured mineral is called troilite, and encased in that is this sort of branch-like sliver looking alloy, which is composed of nickel and iron. It's spectacular to look at visually," Mr Petkovski said.

'You don't cut up a good thing'

John and Paul with the meteorite at Geoscience Australia. (ABC News: Holly Tregenza)

John and Paul were paid $200,000 for their efforts that day on cattle-grazing country in 2016.

They decided not to break the meteorite up into smaller pieces, which is often done to secure more money via multiple buyers.

They said they wanted the meteorite to stay in Australia and be used for educational purposes.

"You don't cut up a good thing," Paul said.

"I wanted it to be in a place where school children can go through and look at it and say, 'yeah, that's Australia'."

"We could've cut it in two and had a couple of doorstops I suppose," John said.

"It's an unreal feeling, that's all we can say, once we found out what we had. I have a lot of grandkids and they all want to see it."