The diamond was first discovered and India, the world's most hard material, mok's hardness of 10. Because it has many excellent mechanical properties, besides being used for decoration outside, in industrial technology is also a wide range of applications, is located in the deep underground rock containing carbon element of kimberley to certain chroma, in high temperature and high pressure condition carbon element and the formation of diamond crystals. The scientists according to this principle, the use of carbon element (graphite) as raw materials, to artificially high temperature and high pressure condition caused by graphite to obtain synthetic diamond and thus in the industry is more common for wide application. Diamond points natural diamond and synthetic diamond, crystal defects and the internal no impurity transparent crystal called gem grade diamond (diamond), it is mainly used for decoration, accounting for 10% of the natural diamond-15%, general than HuangJinGui hundreds of times. Crystals have internal defects (such as inclusion, stain, crack, etc), or because other elements to contain a small amount and internal although no defects but crystal color to the adornment of diamond is not ideal belongs to industrial diamond, used in the manufacture of diamond tools. Cutting tools usually select high-quality diamond. The basic properties of the single crystal man-made and natural single crystal similar, at present the product quality is not stable, with physical material cost and is better than the natural diamond high, but limited its application in cutting tools. Synthetic diamond polycrystalline diamond is composed of many fine particle composition, and with diamond to main ingredients, generally called polycrystalline or gather crystals. Composite films are polycrystalline diamond will compound to hard alloy body a super-hard material, it sets the high hardness and diamond hard alloy body high strength in a body, at the same time a easy welding and polycrystalline diamond characteristic. The diamond tool (including film coated tools), mainly used for various nonmetal materials and non-ferrous metal materials turning, milling, boring, the process. Such as wood, glass, hard plastic, building materials, carbon fiber, ceramics, fire-proof material, copper, aluminum matrix composites, and magnesium zinc alloy etc.