4.4-Billion-Year-Old Crystal Is Earth's Oldest Fragment

The zircon pictured here is now confirmed to be the oldest bit of the Earth's crust. Image courtesy of John W. Valley/University of Wisconsin-Madison. We all know Earth is a pretty cool place, but it’s been cool longer than previously thought. Using two dating techniques, scientists have confirmed that a tiny zircon, a mineral belonging to the group of neosilicates, from Western Australia's Jack Hills region is indeed the oldest fragment of Earth’s crust, dating back 4.4 billion years. The findings, from a team of researchers led by University of Wisconsin-Madison geoscience Professor John Valley, strengthen Valley's theory that the infant planet was cool enough to support oceans and perhaps microbial life just 160 million years after the formation of the solar system.