Pure salt is a mineral with the chemical formula NaCl (sodium chloride).
It can be found in vast quantities in seawater and is also mined as rock salt or halite from basically deposits of ancient evaporated waters.
In its natural form, it is often mixed with other salts and trace substances, so in order to be used for food, it is usually purified and sometimes fortified afterward with iodine or even double fortified with iodine and iron.
There are at least 12 different types of salt to choose from:
1. Kosher salt - the cooking salt with a coarser texture and quick-dissolving versatility.
2. Sea salt - evaporated seawater, coarser than regular table salt.
3. Rock salt - halite, rock salt is salt’s natural form.
4. Fleur de Sel - hand-raked from the surface of tidal pools in Brittany, France, with special wooden rakes, this is the most sophisticated.
5. Table salt - mined from underground salt deposits, finely ground, usually iodized.
6. Flake salt - crunchy crystals of salt.
7. Himalayan pink salt - hand-harvested from the Khewra Salt Mine in the Himalayan Mountains of Pakistan, contains all 84 natural minerals found in the human body.
8. Black salt - Nepalese black salt is a riff on Himalayan pink salt, packed with a blend of herbs, whole spices, and charcoal.
9. Hawaiian salt - Hawaiian salt comes in both red and black colors. Black Hawaiian salt is a combination of volcanic sea salt and activated charcoal, while red Hawaiian salt is unrefined sea salt combined with red volcanic clay, making it rich in iron.
10. Celtic gray sea salt - Sel Gris is a wet salt harvested from tidal eddies along the French coast. Unlike fleur de sel, which is combed from the surface of the saltwater, sel gris is raked from the tidal floor.
11. Smoked salt - has spent a low, slow two weeks over burning wood, taking on the aromatic intensity of whichever wood that might be—whether hickory, applewood, or mesquite.
12. Pickling salt - is the purest of them all: no iodine, no anticaking agents, and no potentially discoloring trace minerals.
References: Read more about Various types of Salt on Wikipedia