Joburg diamonds are rare but, boy, do they have a story to tell. The story told by three diamonds dug up near Klerksdorp more than 80 years ago is of a time when plate tectonics were first beginning to shift deep inside the earth.A group of international scientists from South Africa and Canada have used diamonds to take a peek at what was happening on earth 3.5 billion years ago.The diamonds used in the study came from a collection in Museum Africa in Johannesburg."Ancient diamonds are time capsules. They are messengers from way back then," explains lead author Dr Katie Smart of Wits University.But what makes these diamonds important is that the scientists know their age because they came from the Witwatersrand Supergroup rock formation.By understanding the origins of plate tectonics, explains Smart, scientists can learn more about the origins of life, oceans and even the formation of planets. ..