It is typically formed by the evaporation of salty water (such as sea water) which contains dissolved Na+ and Cl- ions.

First six sodium ions attract to one chlorine ion. then those six sodium ions eatch attract six more chlorine ions. this process keeps on reapeating its self untill you make the almost perfect cube shape of salt

1) "A salt, in chemistry, is defined as the product formed from the neutralisation reaction of acids and bases. Salts are ionic compounds composed of cations (positively charged ions) and anions (negative ions) so that the product is electrically neutral (without a net charge). These component ions can be inorganic such as chloride (Cl−), as well as organic such as acetate (CH3COO−) and monoatomic ions such as fluoride (F−), as well as polyatomic ions such as sulfate (SO42−)." "Salts exist in all different colors, e.g. yellow (sodium chromate), orange (potassium dichromate), red (mercury sulfide), mauve (cobalt chloride hexahydrate), blue (copper sulfate pentahydrate, ferric hexacyanoferrate), green (nickel oxide), colorless (magnesium sulfate), white, and black (manganese dioxide). Most minerals and inorganic pigments as well as many synthetic organic dyes are salts." Source and further information: http://en.wikipedia.org/wiki/Salt_%28chemistry%29 2) "Salt is a dietary mineral essential for animal life, composed primarily of sodium chloride. Salt for human consumption is produced in different forms: unrefined salt (such as sea salt), refined salt (table salt), and iodised salt. It is a crystalline solid, white, pale pink or light grey in color, normally obtained from sea water or rock deposits. Edible rock salts may be slightly greyish in color due to this mineral content." Source and further information: http://en.wikipedia.org/wiki/Salt Further information: http://en.wikipedia.org/wiki/Sea_salt http://en.wikipedia.org/wiki/Halite 3) "1. what is rock salt? This is the common name for the mineral "halite". Its chemical formula is NaCl. You might know this substance as table salt. and... Actually, rock salt is not K2SO4; it is NaCl. It can have impurities of gypsum (CaSO4) and sylvite (KCl) but it is very rare to find potassium sulfate as a mineral, although occasionally polyhalite (K2Ca2Mg(SO4)4.2H2O) is found associated with rock salt deposits. 2. how is it formed? It is typically formed by the evaporation of salty water (such as sea water) which contains dissolved Na+ and Cl- ions. 3. where does it form? One finds rock salt deposits ringing dry lake beds, inland marginal seas, and enclosed bays and estuaries in arid regions of the world. At various times in the geologic past, very large bodies of water (such as the Mediterranean Sea and an old ocean that sat where the Atlantic Ocean sits now) also evaporated and made enormous deposits of rock salt. These deposits were later burried by marine sediments, but since halite is less dense than the materials that make up the overlying sediments, the salt beds often "punched up" through the sediments to create dome-like structures. These are now mostly burried by additional sediments. " Source and further information: http://www.soest.hawaii.edu/GG/ASK/rocksalt.html 4) "Scientific theories behind the origins of sea salt started with Sir Edmond Halley in 1715, who proposed that salt and other minerals were carried into the sea by rivers, having been leached out of the ground by rainfall runoff. Upon reaching the ocean, these salts would be retained and concentrated as the process of evaporation (see Hydrologic cycle) removed the water. Halley noted that of the small number of lakes in the world without ocean outlets (such as the Dead Sea and the Caspian Sea, see endorheic basin), most have high salt content. Halley termed this process "continental weathering". Halley's theory is partly correct. In addition, sodium was leached out of the ocean floor when the oceans first formed. The presence of the other dominant ion of salt, chloride, results from "outgassing" of chloride (as hydrochloric acid) with other gases from Earth's interior via volcanos and hydrothermal vents. The sodium and chloride ions subsequently became the most abundant constituents of sea salt. Ocean salinity has been stable for billions of years, most likely as a consequence of a chemical/tectonic system which removes as much salt as is deposited; for instance, sodium and chloride sinks include evaporite deposits, pore water burial, and reactions with seafloor basalts Since the ocean's creation, sodium is no longer leached out of the ocean floor, but instead is captured in sedimentary layers covering the bed of the ocean. One theory is that plate tectonics result in salt being forced under the continental land masses, where it is again slowly leached to the surface." Source and further information: http://en.wikipedia.org/wiki/Sea_water