What made ​​diamond

Diamond and graphite are allotrope, their chemically identical, are composed of carbon atoms, but different physical properties, simply put, is a soft, one hard.
     Reason for this difference is that they are different forms of atomic crystalline graphite crystal structure is layered, the smaller the force between layers, the lower the force between the external force can easily be destroyed, that is, we say the relatively soft. The three-dimensional crystal structure of diamond, each atom and its  Polycrystalline diamond  atoms have the same large force, and large, extremely large external force required lower intermolecular forces in order to be destroyed, that is, we say particularly hard.
     We usually call it a natural diamond diamonds, natural variations in the long term (eg strong crustal changes), the carbon atom subjected to high temperatures, high pressure forming,  cutting tools  diamond is also manufactured according to this principle: the graphite straight in a special container first heated to a high temperature (2 000 ℃ above), and then suddenly cause a momentary force is applied tremendous pressure (greater than 55 000 atm), after opening the container can be found in graphite diamond grains. These are the main manufacturing process of synthetic diamond.