Simplify the following text for a Grade 9 native English-speaking person.
Original: Zircons from Jack Hills in the Narryer Gneiss Terrane , Yilgarn Craton , Western Australia , have yielded U-Pb ages up to 4.404 billion years , interpreted to be the age of crystallization , making them the oldest minerals so far dated on Earth .
Simplified: Zircons from the Jack Hills in the Narryer Gneiss Terrane , Yilgarn Craton , Western Australia , have yielded Uâ `` Pb ( uraniumâ `` lead radioactive dating ) ages up to 4.404 billion years . This is judged to be the age of crystallization , making them the oldest minerals so far dated on Earth .