The representative salt mineral is  "rock salt"(halite), which has a chemical formula of NaCl and theoretical contents of Na 39.34% and Cl 60.66%. Rock salt is one of evaporite minerals as well as a saline mineral which has the most extensive distribution. It mainly occurs in inland basin's saline lakes, isolated shallow-water lagoons, dried bays and ancient rock salt deposits.

Salt is the most commonly used nonmetallic mineral raw material. Firstly, it is a necessity for the survival of mankind, a material indispensable for maintaining the normal physiological development of human body. Secondly, salt is one of the most basic raw materials for chemical industry. Salt is used in the industry to produce soda ash, caustic soda, chlorine gas, hydrochloric acid, metallic sodium, etc., which in turn are the basic industrial raw materials utilized in chemical, ferrous and nonferrous metallurgical, light, building materials, medical and other industries. Salt is also a daily necessary material for agriculture, animal husbandry and fishery. The number of salt products and their derivatives applied in industry and agriculture amounts to as many as 15,000 in variety. The volume of salt consumption is one of the important indicators for measuring the industrialization level of a nation. So, salt is one of the state strategic materials, occupying an extremely important position in the national economy and people's livelihood.

China is a major country of salt resources. It has a long coastline, about 18,000 km in total length, and is possessed of inexaustible sea salt resources. China is quite abundant in salt mineral resources, too. By the end of 1997, the national total of retained salt mineral reserves verified had amounted to NaCl 384.3 billion tons, being scattered in 18 provinces (regions).

China is a major salt producer as well. China's salt industry has a long history. Accor-ding to a legend, in the reign of Emperor Yan (about 4000 B.C.) a man named Fengsha lea-rnt to produce salt by boiling sea water. The production of lake salt began in the Shang Dynasty of 3000-odd years B.P. and that of well salt started in the Qin Dynasty of 2000-odd years B.P. In the modern times, since the founding of the People's Republic of China, the country's salt-making industry has achieved a swift development and China has become one of the world's  major salt producers. In 1997 China produced 31.62 million tons of crude salt, ranking the world's second, merely next to the United States. Out of China's total output of crude salt, the output of sea salt amounted to 22.44 million tons, holding the first place in the world.