From Dwarf Fortress Wiki
 In Real Life
Rock salt, known officially as halite, is the mineral form of sodium chloride (NaCl). It is found as isometric crystals of a colorless or white appearance. Large deposites of it are found near lakes and seas.
[INORGANIC:ROCK_SALT] [USE_MATERIAL_TEMPLATE:STONE_TEMPLATE] [STATE_NAME_ADJ:ALL_SOLID:rock salt][DISPLAY_COLOR:7:7:1][TILE:'#'] [SEDIMENTARY] [IS_STONE] [MELTING_POINT:11442] [BOILING_POINT:12637] [SOLID_DENSITY:2170]