Diamonds test Earth age theory

Diamonds more than 4 billion years old -- nearly as old as Earth itself -- have been discovered in Western Australia, giv- ing scientists vital clues about the early history of our pla- net.

Found trapped in zircon crystals in the Jack Hills re- gion, the small gems are the oldest identified fragments of the Earth’s crust and sug- gest that the Earth may have cooled faster than previously believed, researchers reported Thursday in the journal Na- ture.

Many geologists have traditionally thought of the period from 4.5 billion to 4 billion years ago as a time when the planet’s surface was a mass of molten lava.

But this discovery challenges that view.