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                        World Diamond Production

                        Natural diamonds are formed at certain conditions of high-pressure and high temperature that only exist at depths of 140 to 190 kilometers (90 to 120 miles) in certain parts of the Earth's mantle. The correct combination of temperature and pressure required to form diamonds is only found in the thick, ancient, and stable parts of continental plates called cratons.  Diamonds formed at depth are brought close to the surface through deep volcanic eruptions, forming igneous rocks known as kimberlites and (more rarely) lamproites.

                        Cratons are restricted to areas of the world including South, Central, and West Africa, Canada, Brazil, Russia, India and Australia - all areas that produce or have produced diamonds. The chart (right) of Global Diamond production shows the relative quantities of diamonds produced by each country

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