Diamond is a crystalline form of carbon under high temperatures and pressures and the hardest mineral known in nature.
It is a rare, precious nonmetallic mineral and plays an important role in the national economy. According to their uses, diamonds can fall into two categories: those that are of high quality and coarse-grained and can be used as decorations are called gem diamonds, and those that are poor in quality and fine-grained and used for industrial purposes are called industrial diamonds.
Gem diamonds are remarkably brilliant, glittering and transparent, reputed as the 'king of gems'. They are highly valued, known as the world's first goods. The levels of their occupancy and consumption are usually considered as the indication for judging the richness of a person and the economic prosperity of a country. Diamonds that are not up to the gem quality are widely used for industrial purposes owing to their great hardness, such as in electromechanical equipment, optical instruments, building, transport, metallurgy, geological exploration and national defense, as well as in high and new technological fields.
According to the trace elements contained, diamonds may be classified into I-type and II-type diamonds. I-type diamonds are mostly ordinary diamonds. II-type diamonds are rare, accounting for only 1%~2% of the total amount; they are mostly used in the space technology and sophisticated industries as they have good thermal conductivity, cleavages and semiconductivity.
Men's knowledge and development of diamonds have a long history. As early as the third century B.C., ancient India had found diamonds. From the beginning of the Christian era to the present, diamonds have always been the symbol of the wealth, power and position of royalty, noble lords and high officials.
Diamond resources are not abundant in the world. In 1966 the world's explored diamond reserve base was 1.9 billion carats, falling far short of the demands of gem and industrial consumption. In the 1960s synthetic diamond technology arose, and by the 1990s the technology has been perfected. The synthetic diamond has almost all replaced the natural industrial diamond, and its consumption has taken up over 90% of the world's industrial diamond consumption. The major diamond producers are Australia, Russia, South Africa, Botswana and Congo (Kinshasa) (former Zaire).Henan Hongxing Mining Machinery Co., Ltd is the professional manufacturer of complete sets of mining machinery, for example,classifier,ball mills Welcome all of you to visit our official website.mobile jaw crushers:http://www.hx-china.com/6.html
Diamonds were found in China about 200 to 300 years ago. Between the Ming and Qing dynasties (in c. the 17th century), farmers in Hunan Province panned river sands and reco-vered diamonds from the placers. Geological exploration for diamonds began in the 1950s. Up to now six famous diamonds, each with a weight greater than 90 carats, have been found in China; for example, 'the Changlin diamond' weighs about 158 carats.
Diamond resources are relatively poor in China. Through nearly 50 years of geological work diamond reserves have been explored only in Liaoning, Shandong, Hunan and Jiangxi provinces. Up to the end of 1997, the retained diamond reserves in China were 20.7257 million carats, which did not occupy an important position in the world. In terms of quality, diamonds produced by Liaoning Province are of excellent in quality and gem diamonds make up about 70% of the total production. Since the 1990s, China has produced about 10,000~15,000 carats of diamonds per year, which falls far short of the domestic consumption. More than 99% industrial diamonds rely on home-made synthetic diamonds. In 1997 China's synthetic diamond production reached 440 million carats. The natural industrial diamonds occupy a very limited proportion of the consumption.