Salt, the most popular food seasoning, 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 iodized 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.

Chloride and sodium ions, the two major components of salt, are necessary for the survival of all known living creatures, including humans. Salt is involved in regulating the water content (fluid balance) of the body. Salt flavor is one of the basic tastes. Salt cravings may be caused by trace mineral deficiencies as well as by a deficiency of sodium chloride itself.

Overconsumption of salt increases the risk of health problems, including high blood pressure. In food preparation, salt is used as a preservative and as a seasoning.

Salt is not just a happy condiment, it is an essential life ingredient, and the primary means of preserving both food and drink before refrigeration. To the Romans it was one more good reason to invade Gaul. In the sixteenth century the insidious salt tax extended to the western parts of France, causing active revolts. According to French food historian Maguelonne Toussaint-Samat, the rabble of Bordeaux evidently grabbed the bureaucrat who administered the tax, cut him up, and salted his parts, much as they would have ministered to a fattened pig. And by the time of the Revolution, the then centuries-old salt tax, mixed with famine after a poor grain harvest, was a further incitement to overthrow the aristocracy, who, naturally paid no salt tax.

Salt, too, I discovered not only has color – gray salt is the most reminiscent of the sea – but also perfume. Experts can apparently sniff out the difference among salt from mines, salt of the sea, sea salt skimmed first from the surface of the flats, and salt from below, slow to appear after evaporation. My nose for salt is sadly undeveloped, though a faintly brackish, slightly geranium-leaved aromatic scent did begin to take vague olfactory shape.