The world's oldest known diamonds have been found covered in a crystal in Western Australia, scientists say.

The minuscule gemstones are 4.25 billion years old and could provide a unusual glimpse into Earth's distant geologic past.

"No one would have actually predicted that diamonds were in there," said Simon Wilde, a geologist at Curtin University of Technology in Perth and a member of the team that made the find.

The discovery suggests that seas of molten lava that covered primeval Earth had cooled down faster than had previously been thought.
The find also suggests that plate tectonics, the process by which large shelves of Earth's crust move to create geologic activity may have already been started.

"A diamond would never form in a magma ocean," said Thorsten Geisler, a geologist at Westfalische Wilhelms-Universitaet in Munster, Germany, and another team member.

The discovery is a shocker to geologists, many of whom believed that the molten lava and volcanic activity persisted on Earth's surface for at least 500 million years after our planet formed some 4.5 billion years ago.

Source: http://news.nationalgeographic.com