The Oldest Rock in the World Tells Us a Story
It’s hard to imagine how this teeny little rock â€” it’s not even a whole rock, it’s just a grain, a miniscule droplet of mineral barely the thickness of a human hair â€” could rewrite the history of our planet. But that’s what seems to be happening.
This piece of Zircon, an extremely durable mineral found all over the world, turned up in a dry, hilly region of Western Australia. It was sitting inside a larger rock, and when scientists checked, it turns out this little grain formed around 4.4 billion years ago. That would make it the oldest rock we’ve ever seen on this planet, old enough to know secrets about early Earth, old enough to tell us a little something about how life started here. After all, this planet, geologists say, is only 4.5 or 4.6 billion years old. So this little grain has been around since almost the beginning â€” but not quite.