Salt, or sodium chloride, is a crystalline mineral with the chemical formula NaCl. Salt is essential to life, not only regulating fluid levels in the body, but sodium ions are used by the nervous system for signaling purposes. Salt has been harvested from the ocean, saline lakes, or mined for thousands of years, with archaeological evidence of salt gathering dating back to 6,000 BCE.
Until modern processes made it inexpensive, trade in salt was hugely important, and salt was as expensive as gold. In fact, words like salary and salad come from the Latin word for salt -- Roman soldiers were paid a stipend so they could purchase salt, and salted leafy greens were an important part of their diet.
Depending on where salt is mined or harvested, other mineral impurities can exist. Unrefined sea salt also contains magnesium, calcium and potassium, which along with sodium are the human bodies major electrolytes. Most of the salt commercially produced is refined, which removed everything by the sodium chloride. A trace of anticaking agents are added, and the white, fine grained salt is packaged. In other parts of the world, salts are produced that can be pink, black, red or green. Salt can be smoked over various woods and used to finish dishes.
In cocktail use, salt not only decreases bitter flavors and magnifies sweet flavors, but also adds to the aroma of drinks.