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Earth's Crust - Could the Jack Hills Zircon be its Oldest Piece collected to date? - NaturPhilosophie
Zircons are Forever The oldest remaining grain of early Earth's original solid rock crust has now been confirmed to be a 4.374-billion-year-old Jack Hills zircon crystal from Australia. That age should settle a scientific debate over the accuracy of that mineral's internal clock, and cuts the time from when Earth was hit by a Mars-sized body $ ($which led to the formation of the Moon$ )$ and the cooling and creation of Earth's first solid crust from 600 million years to 100 million years. Scientists dated the crystal by studying its uranium and lead atoms. Uranium decays into the latter very slowly over time and can be used like a clock.