The zircon crystal, a beautiful nesosilicate crystal gem found buried on a sheep ranch in western Australia, is the oldest known piece of our planet ever found, confirms scientists.
According to Reuters on Sunday, the crystal back dates to 4.4 billion years ago. To put it mildly, a true “gem of a gem,” writes Reuters.
The crystal is from the Jack Hills region of Australia. Two different age-determining techniques – radioactive uranium decay and atom-probe tomography – were used to date the age of the crystal. The crystal is very small, measuring only 200 by 400 microns, about twice the diameter of a human hair.
In a graphic provided by Reuters, and carried by the Chicago Tribune, the crystal’s timeline dates back to a period shortly after the Earth and its core was formed. It was during this “cooling period” that the gem was thought created.
John Valley, a University of Wisconsin geoscience professor who led the research, said a study of the crystal has led to changes about what we know of the formation of Earth and its crust.
To put that age in perspective, the Earth itself formed 4.5 billion years ago as a ball of molten rock, meaning that its crust formed relatively soon thereafter, 100 million years later. The age of the crystal also means that the crust appeared just 160 million years after the very formation of the solar system.
The finding supports the notion of a "cool early Earth" where temperatures were low enough to sustain oceans, and perhaps life, earlier than previously thought, Valley said.
This period of Earth history is known as the Hadean eon, named for ancient Greek god of the underworld Hades because of hellish conditions including meteorite bombardment and an initially molten surface.
"One of the things that we're really interested in is: when did the Earth first become habitable for life? When did it cool off enough that life might have emerged?" Valley said in the telephone interview with Reuters.