Montmorillonite clay was named after the town of Montmorillon, France, where it was first identified. The mineral clay belongs to a group of clays known as smectite, a word that describes its layered structure. The smectites are one of seven clay mineral groups. Each group contains a certain number of species, variations on the layered structure. Clay minerals come in many different shapes and sizes to produce a wide variety of clays.There are seven groups of clay: Kaolin group Illite group Smectite group Chlorite group Vermiculite group Mixed-layer group (consists of all five groups above) Lath-form group
All clays will adsorb. However, the smectite group is the only group capable of absorption. Most clays sold in the health food industry belong to the smectite category.
While it absorbs toxins and bacteria like the other clays, it primarily acts as a bulking agent and in anti-diarrhoeal medications. Some companies add kaolin to food supplement due to its mineral content.
The illite group is named for the state of Illinois. The best-known species of illite is glauconite (a green mineral clay). It is typically found in clays of marine origin. Other colors include white and yellow.
SmectiteSmectite is characterized by its expandable properties. Unlike the other clays, only smectite can absorb toxins. This qualifies its structural uniqueness and sets it apart from all other clays. For this reason, smectite has become a favorite clay for industrial and dietary use. The most familiar species of smectite is montmorillonite. Again, it is the most preferred species of edible clay. Most clay research has been done with montmorillonite. What makes montmorillonite special?
The montmorillonite minerals occur in very small micron sized particles. They are extremely fine-grained and thin-layered, more than any of the other clay minerals. The layers contain ions that are very loosely bound to one another and easily exchangeable. Not only will the toxins stick to its outside surface, but numerous elements and organic matter will enter the space between the layers.
In addition to its already unique structure, montmorillonite has a particularly large surface area when properly hydrated in water, which further boosts its adsorptive and absorptive properties. Chemically and structurally, it is shaped like a credit card, with negative charges on the flat surface and positive charges on the edges. Therefore, the negative charge (the good one) is many times more powerful that the positive charge. Montmorillonite is a more complicated clay and has a higher exchange capacity than the simpler species of clay, such as kaolinite. Its ability to adsorb and absorb toxins is greater than that of the clays in the other groups.According to one article on clay (Lei 1996), a mineralogist at Massachusetts Institute of Technology, Robert T. Marin, stated that one gram of this clay has a surface area of 800 square meters. To give that some serious perspective, that's about ten football fields! The greater the surface area of the clay, the greater the power to pick up the positively charged particles or toxins many times its own weight.
Any given clay is usually a mixture of clay minerals, one or two minerals almost always being predominant. Clays are rarely found separately and are usually mixed not only with other clays but with microscopic crystals of quartz, mica, feldspar, and carbonates. Most clay contains montmorillonite to a greater or lesser degree. The available types of montmorillonite vary in color, consistency, and shape. The color may be white, gray, or tan, with tints of yellow or green. Typically, montmorillonite will be included in a mixture of clay groups in any given material; all six groups will most likely contain particles of montmorillonite.
Sodium-bentonite is a commonly and highly utilized industrial clay. Currently, several companies are selling calcium bentonite in health formulas. Bentonite is widely distributed in nature. Its name was derived from the Fort Benton series of cretaceous rocks in Wyoming, where it was first found. The name can be misleading; sodium-bentonite is not a mineral name but a trade name for a commercially sold swelling clay. It is often used in commerce as a name for montmorillonite, and sometimes the names are used interchangeably. Smectite is the general group name used by mineralogists.The source of bentonite is weathered volcanic ash. In marine environments, the ash transforms itself, over time, to smectite. There are several species in the smectite group, montmorillonite being one of them. Depending on its source, bentonite may contain a high percentage of montmorillonite or just a tiny bit. The rest of the contents may either be related or a completely different mineral group. Rarely does 100 percent pure smectite occur: therefore, not all bentonite is a pure smectite. Quite commonly, the clay minerals illite or chlorite are present in alternating layers.
Bentonite is sometimes wrongly sold under the montmorillonite label or, at least, the name doesn't give any clear indication of its contents. There are a wide variety of bentonite clays that looked, felt, tasted, and acted differently from the others. They did so because they were not the same clays. The variation in minerals does not really matter in industrial use, so long as the bentonite has good expansion capacity. But the guidelines for industry use do not hold for the consumption of clay.Single-and Mixed-Clay Minerals Typically, any given clay material may be composed of particles of a single clay mineral or a complex of many different naturally occurring minerals. It is not easy to find pure samples of many clay minerals. When they are found in nature, like a vein of gold, they are painstakingly mined. Otherwise, scientists depend on preparing single-clay minerals in the laboratory. Most commonly in nature, layers of one type - for example, montmorillonite - are interlayered with units of another type, for example, illite. In other words, a tiny particle may be composed of successive layers of illite and montmorillonite. This of course varies according to the region of the deposit and the climate. Climatic effects influence the occurrence of certain minerals.