Chemically, table salt consists of two elements, sodium (Na) and chloride (Cl). Neither element occurs separately and free in nature, but they are found bound together as the compound sodium chloride. It occurs naturally in many parts of the world as the mineral halite and as mixed evaporites in salt lakes. Table salt, when viewed with a magnifying glass, can be seen to consist of tiny, cube-shaped flakes.

Source: NASA Aquarius