"Natural" Salts
You may be told, "Salts from ancient sea beds provide a full spectrum of minerals that have been depleted from our soils and foods." However, this mineral-depletion claim won't stand up to scrutiny. The unrefined salts do contain a variety of contaminating minerals but in extremely small amounts. Magnesium and potassium are the ones most often raved about. However, an ounce of Celtic Sea Salt contains only about 0.026 grams of potassium compared to 4.55 grams in just 1 pound of hay. Magnesium in Celtic Sea Salt is about 0.09 grams versus 0.91 grams in just 1 pound of hay.
Confronted with that logic, talk often turns to a large array of trace and ultratrace minerals in unprocessed salts. For the nutritionally important minerals, only the level of iron matches or exceeds levels present in the horse's basic diet-and horses are already getting much more iron than they need. Minerals that we know are often deficient, like copper and zinc, are in these salts at only 1/100th of their level in hay, if that.
There's also a long list of more exotic minerals, like Yttrium, in the analyses and some more familiar but unsavory items like lead and radon. The claim these are present as rich, ancient earth levels simply doesn't hold up since evaporated sea salts, from "today's" seas, have similar exotic mineral profiles. A check of the U.S. Geological Service data also shows abundant levels (relative to the salts) in plain ol' dirt or sand.
Colors of Natural Salts
Pure sodium chloride is white. Salts with many magnesium salts may be exceptionally bright white. Seawater salts evaporated in clay flats can be tannish/gray from clay contamination, as can mined salts. Brownish red colors could come from iron salts in very high amounts, but red and pink coloration is usually caused by high numbers of salt-loving bacteria, called halobacteria, that thrive on salt and are trapped inside the deposits. (There's a pink salt lake in California.) Brown/black discoloration is plain old dirt, sometimes volcanic ash. Halite that is amber or blue has been exposed to natural radiation (several of the minerals found in halite deposits are potentially radioactive).
Another claim is that it's the balance of minerals from the sea that makes them nutritionally superior. After all, life evolved from the sea and if you take a sea-dwelling creature and try to keep it alive in water made salty with plain table salt, it will eventually die. Fish do get some of the minerals they use from their water, just like humans and land animals and fresh water fish do, but they get far more from the solid food in their diet.
All living things need salt and many other minerals, but it's simply not true that all minerals dissolved in the sea are necessary for life. Some are toxic-although not at toxic levels in natural salt products with the exception of fluorine in some mined/rock salts.
Bottom Line
Natural salts from mined salt deposits or evaporated sea water are nothing more than "dirty" table salt. The same raw salts that are used to make white salt are the salts in pricier products. Natural salt deposits are found all over the world and, whether mined or evaporated from ocean water, are similar. Differences in extraction and degree of contamination can produce slightly different mineral profiles but nothing that amounts to anything of importance for the horse.
About the only reason we see for buying a "designer" salt would be for a horse that dislikes the taste or texture of refined salt but consumes raw salt. Otherwise, you're paying up to 70 times more for a product that should actually cost less than table salt.
