Diamonds are crystal forms of the element carbon. It is a material that is basically composed of pure carbon. In nature, hot carbon-rich fluids undergo a process of crystallization to turn into diamonds. Extreme heat, about 1800 to 2200°F (or 1000 to 1200°C), and tremendous pressure, about 50 kilobars, is needed for the crystallization process to be possible.
The temperatures and pressures that are conducive to the formation of natural diamonds can only be found under the earth’s surface. Experts believe that some diamonds are formed as deeps as 420 miles or 670 km beneath the earth’s surface. Concentrations of naturally occurring diamonds that is large enough to be economically practical for mining are commonly located in the world’s oldest continental regions called the cratons. Craton conditions are very conducive for diamond formation and preservation.
A great number of diamonds are usually recovered at a considerable distance from where they were initially deposited. Flowing veins of liquid magma act as carriers of diamonds from deep underground towards a shallower surface. Glaciers and winds can also act as a transport medium for diamonds from one point to another in Earth’s surface.
Small and typically low quality diamonds are formed in rocks at shallower depths with heat and pressure that is considerably higher than usual for those depths. Some diamonds are can be found within meteorites and around meteorite crater sites. A number of diamonds are manufactured synthetically under in a laboratory by using machines to mimic the exact temperature and pressure needed to form diamonds. Like naturally occurring diamonds, these artificial ones can be used in jewelry or for industrial use.