Diamonds, composed almost entirely of carbon molecules, crystallize and form under intense heat and pressure about 150 kilometers down and within the Earth’s mantle, just above the Earth’s molten core.


At one time or another, a vent or pipelike opening occurs starting beneath the mantle where the superhot molten material exists. A crack in the base of the mantle opens into the pipelike vent and the molten flow shoots upward under volcanic-like pressure carrying with it surrounding material containing the formed diamonds within it. This wondrous elevator ride to the surface carries diamonds in two types of magma – kimberlite and lamproite.



Since it has never been possible to observe nature forming a diamond in the rough within the Earth’s mantle, we cannot say with precision exactly how long the process takes. We do know, however, that when all conditions are perfect, all elements precisely in place at one time, that it is only a matter of a few days for carbon atoms to be transformed into rough diamond structure. But it then might take millions, if not a billion, years before natural color diamonds are formed and can surface where they can be discovered.