Today, halite is a cheaply-produced commodity extracted from the subsurface in mines, or salt solution plants, or produced at the surface in saltpans. In the production of table salt, processing, packaging and marketing are the major costs for most salt manufacturers. An interesting exception to the low sale price of modern table salt is the artisinal “Fleur de Sel de Geurande” a delicate gourmet form of white seasalt that is still hand-produced on fens along the coast of Brittany. It costs ≈US$40/kg and is produced by “paludiers” only on suitable summer days when halite rafts can be raked from the brine surface of specially maintained coastal salt pans, which are floored with grey clay.
A paludier raking halite rafts in coastal pans on the fens of SW France (imaged by Claude Rannou)
According to the local legend, salt flowers only form on hot days when the wind blows from the east (from the sea). It and the cheaper grey salt (sel gris), which is scraped from the pan floors and also prized by gourmands, has been produced this way in French coastal fens since Pre-Roman times. The flowers of salt are marketed as a "natural" product that contains all 84 trace elements and micronutrients found in the sea, and as being a natural source of potassium, calcium, copper, zinc and magnesium. This halite product has an intense white colour, with a rigid crunchy crystalline structure and high moisture content giving it a distinct "feel on the tongue." This is because "Fleur de Sel "is composed of clusters of halite rafts. These rafts formed on the brine surface, as a thin layer of floating salt crystals, which are harvested daily via raking and then placed on plastic sheets to dry in the sun, making it a highly labour-intensive product.
The "flower of salt" product is packed with no other processing, unlike what happens to industrially-produced sea salt that undergoes a process that typically consists of varying combinations of washing, centrifugation and drying by the heat of combustion, grinding and sieving and the addition of iodine to prevent thyroid problems like goitre. While large saltwork companies need several square kilometres for salt pan installations, a "flower of salt" product can be obtained in ponds with total areas smaller than 0.1 hectare. There is a definite economic upside to the artisanal production of "flowers of salt." Since it is a handmade product, small salterns can be constructed/operated by family groups, so offering a new or supplemental income source for low-income populations living in or near hypersaline strandlines.
Impurities like clay are called grey spot or black spot in highly efficient mechanised salt production plants across the world and are considered undesirable in the processed end-product. To the cynical, it says something about modern French marketing skills, and perhaps the gullibility of middle-class gourmands with too much money and time on their hands, that each year the gourmet industry successfully markets un-processed, non-iodised, dirt-polluted salt (sel-gris) scraped from pan floors for top prices.
The various untreated salt products from France, the Himalayas and elsewhere are typically marketed as a “natural organic” product, “completely untreated” so it retains all its “essential nutrients.” Such blanket claims from marketers targeting a moneyed, health-conscious and “new-age” mostly middle-class demographic, should at times be taken with a grain of salt. For example, some types of Himalayan “natural” salt produced from high altitude continental lakes in Tibet, is iodine deficient, another widely utilised source of gourmet salt is a crushed salt mine product, mostly from the Khewra Mine, Pakistan, which is not really a completely untreated product. Then again, an impurity-rich pink salt demands visual attention on a gourmet table.
"Natural" lake salt in Tibet has led to high levels of cretinism and other thyroid problems in the local peasant population. Some remote mountain villages in Tibet have birthing data that show 13% of newborns suffer from cretinism. This is because of low iodine levels in the soils and the fact that local salt is harvested from salt lakes where glaciation and deep weathering have long ago removed iodine from soils and associated salts.
Unlike seasalt, the present soil waters and runoff, that ends up collecting and evaporating in the salt lakes, contains little or no iodine (Lee, 2001). Salt harvested from the Tibetan lakes, when carried to the villages and sold, is 50 % cheaper than salt that has been fortified (sprayed) with iodine.
A lower cost makes natural local salt a more attractive product to peasants in the villages, most of whom are subsistence-level farmers. Harvested salt is usually bartered or exchanged for an equivalent weight in rice. In an attempt to improve the health of the people, selling non-iodised salt has been made illegal by the Chinese government. But a lower price and the fact that the salt harvesters usually barter their salt for an equivalent weight in rice, and have done so for hundreds of years, make the harvested natural salt more attractive than the more expensive iodized product. To maintain their own subsistence level livelihoods, the salt harvesters have spread and encouraged rumors that animals and people fed iodized salt will be infertile. In rural China and Mongolia, the Chinese government’s policy of introducing iodized salt to the agrarian population has been much more successful than in religious regions of Tibet. In the 1980s the rates of goiter (indicated by an enlarged thyroid and an indicator of iodine deficiency) in the general population of China were as high as 40 %. By making non-iodized salt illegal and keeping the price of the iodized salt low, the current rate of goiter in the general Chinese population is now somewhere near 5 %. Iodization programs in salt and milk products in the western world since the 1920s had largely eliminated the problem of iodine-deficiency by the 1960s.
Ironically, in some in parts of the western world now lacking a government-enforced iodine program, the populist anti-science “new-age” push for healthier back-to-nature, vegan and organic food products is an evergrowing and ever more profitable market trend. Accordingly, there has been a move away from iodised salt and iodised milk to make it more “natural.” Now the rate of incidence of iodine-deficiency in the general population, and in children especially, is growing once more in many parts of the developed world.
For example, in Australia in 2003 the iodine intake in the population was half what it was five years earlier, but most Australian adults were unaware they were recreating the problem of iodine-deficiency in their children (Li et al, 2001). Based on a more recent 2010 WHO study, it appears the problem in Australia has grown even further (Sydney Morning Herald Newspaper, Oct 10, 2010). The WHO study, which focused on almost all the babies born in the state of Victoria from 2001 to 2006, found clear signs of iodine deficiency in many Australian newborns. About 26,000 of the 368,000 newborns, or about seven per cent, were found to have elevated concentrations of thyroid-stimulating hormone (TSH) caused by the body’s compensatory response to a poor intake of iodine. A smaller NSW-based study found 5-8 per cent of newborns in that state from 1998 to 2000 were iodine deficient. The WHO considers a population to be iodine deficient if more than three per cent of neonatal blood samples show elevated TSH concentrations.
New-age anti-science and anti-industrial mantras, now followed by an increasingly scientifically-uninformed proportion of the Australian adult population, have returned the status of Australia’s newborn population to that of “iodine deficiency.” Some states in Australia are now considering legislation to make iodised flour mandatory in bakery products.
Likewise, the use of "natural" or “untreated” salt from Lake Magadi and Natron as a food additive has led to significant health problems (fluorosis) in the local population due to “naturally” high levels of fluorine in the harvested salt (Vuhahula et al., 2009).
Stones cut flat for evaporating seawater to extract salt. Yangpu Ancient Salt Field archeological heritage site in Yantian village, Yangpu Peninsula, Hainan, China (from Wikipedia). The area comprises more than 1,000 stones, cut flat on top, which are used to evaporate seawater to produce salt. The stones have a thin rim around the edge to contain the water. During high tide, the surface of the stones becomes filled with seawater. During low tide, this evaporates, leaving the salt, which is then collected.The area was established around 800 AD when a group of salt workers from Putian city in Fujian province moved to Yangpu. Today, only a small group of villagers continue to make salt using this method and it is not their main source of income.