Researchers working in Western Australia have discovered the oldest fragments of the Earth' s early crust that have yet been identified: microdiamonds  These microscopic crystals measure only 50 microns across and were formed 4  2 billion years ago
This discovery sheds light on how long it took for the Earth' s crust to form, since this date is only 300 million years after the formation of the Earth itself
The Earth's crust took no longer than 300 million years to start to form.