Usually, boron nitride is graphite structure, commonly known as white graphite. The other is diamond type, which is similar to the principle that graphite is converted into diamond. Graphite boron nitride can be transformed into diamond boron nitride at high temperature (1800℃) and high pressure (800Mpa). The bond length of B-N in this boron nitride (156pm) is similar to that of C-C in diamond (154pm), and its density is similar to that of diamond. Its hardness is equivalent to that of diamond, but its heat resistance is better than that of diamond. It is a new type of superhard material with high temperature resistance, which is used to manufacture drills, abrasives and cutters.