Common salt is a mineral substance composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of ionic salts; salt in its natural form as a crystalline mineral is known as rock salt or halite. Salt is present in vast quantities in the ocean where it is the main mineral constituent, with the open ocean having about 35 grams (1.2 oz) of solids per liter, a salinity of 3.5%. Salt is essential for animal life, and saltiness is one of the basic human tastes. The tissues of animals contain larger quantities of salt than do plant tissues; therefore the typical diets of nomads who subsist on their flocks and herds require little or no added salt, whereas cereal-based diets require supplementation. Salt is one of the oldest and most ubiquitous of food seasonings, and salting is an important method of food preservation.
Salt is produced from salt mines or by the evaporation of seawater or mineral-rich spring water in shallow pools. Its major industrial products are caustic soda and chlorine, and it is used in many industrial processes. Of the annual production of around two hundred million tonnes of salt, only about 6% is used for human consumption; other uses include water conditioning processes, deicing solutions and agricultural use. Edible salt is sold in forms such as sea salt and table salt which usually contains an anti-caking agent and may be iodised to prevent iodine deficiency. As well as its use in cooking and at the table, salt is present in many processed foods. Too much sodium in the human diet raises blood pressure and may increase the risk of heart attacks and strokes.
Although salt is a requirement for most carbon based lifeforms, some species like the Shaill and others like them as well as some amphibians such as an Ult could be seriously hurt if not killed by salt bombs.