<P> Diamonds are far from evenly distributed over the Earth . A rule of thumb known as Clifford 's rule states that they are almost always found in kimberlites on the oldest part of cratons , the stable cores of continents with typical ages of 2.5 billion years or more . However , there are exceptions . The Argyle diamond mine in Australia , the largest producer of diamonds by weight in the world , is located in a mobile belt , also known as an orogenic belt , a weaker zone surrounding the central craton that has undergone compressional tectonics . Instead of kimberlite , the host rock is lamproite . Lamproites with diamonds that are not economically viable are also found in the United States , India and Australia . In addition , diamonds in the Wawa belt of the Superior province in Canada and microdiamonds in the island arc of Japan are found in a type of rock called lamprophyre . </P>
<P> Diamonds are far from evenly distributed over the Earth . A rule of thumb known as Clifford 's rule states that they are almost always found in kimberlites on the oldest part of cratons , the stable cores of continents with typical ages of 2.5 billion years or more . However , there are exceptions . The Argyle diamond mine in Australia , the largest producer of diamonds by weight in the world , is located in a mobile belt , also known as an orogenic belt , a weaker zone surrounding the central craton that has undergone compressional tectonics . Instead of kimberlite , the host rock is lamproite . Lamproites with diamonds that are not economically viable are also found in the United States , India and Australia . In addition , diamonds in the Wawa belt of the Superior province in Canada and microdiamonds in the island arc of Japan are found in a type of rock called lamprophyre . </P>
where do most of the worlds diamonds come from
where do most of the worlds diamonds come from
The Argyle diamond mine in Australia
The Argyle diamond mine in Australia