A zircon crystal small enough to sit on a fingertip, found in the Jack Hills of Western Australia, has been dated to 4.404 billion years old, right around the same moment a 2025 study says the Moon itself finished crystallizing

In the Jack Hills of Western Australia, a grain of zircon small enough to sit on a fingertip has been dated to 4.404 billion years old, and a 2025 study puts the Moon’s own final crystallization at almost exactly that same moment. This is one of the oldest known fragments of Earth, and it may be roughly as old as a finished Moon itself, or very close to it. That durability is the entire reason Jack Hills zircons exist to be studied at all. A Moon that took its time finishingThe Moon-forming impact itself was fast, but the Moon it produced was not instantly solid. What I find genuinely strange about thisIt’s not just that the crystal is old.