To mineralogists rock-salt is often known as halite - a name suggested in 1847 by E.
Pure halite consists only of sodium chloride, but salt usually contains certain magnesium ccmpounds rendering it deliquescent.
Halite; Die Naturgeschichte der arthrodelen Flagellaten (1883); Butschli, " Mastigophora " (in Bronn's Thierreich, i.
Halite may occur as a sublimate on lava, as at Vesuvius and some other volcanoes, where it is generally associated with potassium chloride; but its usual mode of occurrence is in bedded deposits, often lenticular, and sometimes of great thickness.
The word halite, however, is sometimes used not only for the species rock-salt but as a group-name to include a series of haloid minerals, of which that species is the type.