<P> Table salt or common salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in its natural form as a crystalline mineral is known as rock salt or halite . Salt is present in vast quantities in seawater, where it is the main mineral constituent . The open ocean has about 35 grams (1.2 oz) of solids per litre, a salinity of 3.5% . </P> <P> Salt is essential for life in general, and saltiness is one of the basic human tastes . Salt is one of the oldest and most ubiquitous food seasonings, and salting is an important method of food preservation . </P>

What is the main ingredient in table salt