The gem is a carbonado, one of the toughest forms of natural diamond. Black diamonds are usually about 2.6 to 3.2 billion years old - a time before dinosaurs existed. The Earth itself is around 4. ...

A billion-year-old black diamond, believed to be the ... The gem is a carbonado, which is one of the toughest forms of natural diamond. Carbonados are extremely rare and have only ever been ...

Only known to exist in Brazil and the Central African Republic, “carbonado” black diamonds date from around 2.6 to 3.8 billion years ago and are an extremely rare natural occurrence.