Animated coloured scanning electron micrograph (SEM) of Sea salt crystals on the surface of coralline alga. Salt crystals formed when a coralline alga was dried. Salt is a mineral that it necessary for the survival of life, especially humans. It is compose of primarily sodium chloride. It is a crystalline solid, white, pale pink or light grey in colour, obtained from sea water or rock salt deposits. There are different forms of salt for human consumption: unrefined salt (such as sea salt), refined salt (table salt), and iodized salt. Over consumption of salt can increase the risk of health problems, including high blood pressure. In food preparation, salt is used as a preservative and as a seasoning.