EARTH - Diamonds in Earth's oldest zircons are nothing but laboratory contamination

As is well known, the Earth is about 4.6 billion years old. No rocks exist, however, that are older than about 3.8 billion years. A sedimentary rock section in the Jack Hills of western Australia, more than 3 billion years old, contains within it zircons that were eroded from rocks as old as about 4.3 billion years, making these zircons, called Jack Hills zircons, the oldest recorded geological material on the planet ...

http://phys.org/news/2013-12-diamonds-earth-oldest-zircons-laboratory.