The diamonds are believed to date back more than four billion years, making them almost as old as the 4.5 billion year old planet, according a report from Australian and German researchers in the scientific journal Nature.
"We're still stunned, it was the last thing we expected to find," geologist Alexander Nemchin from Western Australia's Curtin University of Technology told AFP.
The diamonds were found trapped inside zircon crystals from the Jack Hills region in the remote north of Western Australia state.
The 50 gems are tiny, with the largest measuring only 70 microns, or about the width of a human hair and most invisible to the naked eye.
Nemchin said they could have major implications for scientists trying to understand the Earth's early geology because they are believed to have formed up to a billion years earlier than the oldest previously discovered diamonds.
He said diamonds need immense pressure from the planet's tectonic plates to form, and scientists had believed the plates were too thin so early in Earth's history because at the time it was little more than a molten ball.
"It means it's possible that the Earth looked similar to the modern Earth much earlier than we thought," he said.
"It's a very controversial area though and not everyone will agree with that conclusion."
Last Mod: 23 Ağustos 2007, 16:00