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water.  Curiously, the common name of this silica as a mineral, is opal.    Diatoms are perhaps the most abundant aquatic creatures and provide food for a multitude of lake creatures and sea life.
     When diatoms die, their silica shells accumulate by the billions as sediment. Thick layers of these diatom shells have become fossilized in rock or left more loosely packed in shales and clays.  While their remains also may make up diatomaceous earth, or diatomite, more importantly they also help to make-up vast amounts of various different minerals when their silicon combines with other elements.

How this is done is extremely important.  If ingested by an algae-eating tadpole that is in turn fed upon by a fish that is later injured and dies and then eaten by crayfish, several opportunities for chelation have taken place.  Each life form has become a part of the food chain and been recycled before and after becoming sediment.  Certain elements are bonded to proteins thereby, and/or are suspended between amino acids.  The molecules they form may either become colloids in association with Aluminum, as they form clay, or even smaller particles absorbed by the clay.  The clay can also become absorbed in fulvic acid coming from the run-off over composted vegetable matter, or absorb certain organic matter independently.  Evidence of these processes are visible in sedimentary layers.

     Certain deposits of Montmorillonite, like the one in Panaca, Nevada, rich in humates, not only make an ideal fertilizer additive as a result, but the resultant fulvic and humic acids in mild doses are also very beneficial to higher life forms.   Thus, the clay Montmorillonite not only has absorbed other elements, and was absorbed by once-living organisms, the matrix occurs in a natural state, as formulated by Mother Nature.  Artificial chelation can be synthesized using factory chemistry, but minerals cannot.   Silicon harvesting algae/diatoms and partially decomposed algae observed as lignitic silts enrich some deposits of Montmorillonite and have had eons of time to ionize and mineralize into forms more readily assimilatable by other organisms.  These living clays are not overburdened with high amounts of Calcium or Sodium, nor withuseless or toxic free elements in their metallic state, nor certain heavy metals because of the aforesaid process.   Ideally, their pH will be close to neutral and they can be used as soil balancers to boot.  

         More than just another Bentonite
     The particular Montmorillonite quarried by Window Peak Trace Minerals requires no blasting, tunneling, grinding or hammer milling to prepare.  It does not come from strip mining because overburden was already removed during the last several thousand years by weathering after seismic activity exposed the desert deposit.  The characteristically light rainfall patterns have further left the basic mineral pattern intact with virtually no leaching having taken place, leaving a uniform concentration of trace minerals throughout.
     It was obviously formed in a fresh water environment because no Sodium chloride, or halite (sea salt/table salt) is detectable in its composition.  In fact its low- Sodium, low-Calcium confirm that it is not classically, a Bentonite.   Successive studies from various scattered test samples consistently evidence fulvic acid and humic acid contents in the 9% and 1% ranges, respectively, with pH always falling within 6.7 –7.3.  If it were Sodium-based or Calcium-based the pH would be much more alkaline and therefore inappropriate for most western soils.  On the other hand, as a soil amendment it is a relatively simple matter to add rock gypsum to acidic soils, but this measure alone does not constitute a conscientious soil amendment program.  One must think about the health of the soil and all of the factors that must be synergistically involved to create good humus.

“Manufacturing” methods
     The loosely compacted sedimentary state of the Montmorillonite from Panaca is merely freed up by use of traditional farm implements and screened at low temperature to preserve its integrity.   
Chelated, colloidal, ionic Montmorillonite with organic matter in Lincoln County, Nevada showing plowed (left) and rotovated (right) surface-exposed material.  Notice the basaltic formations in the background giving rise to many of the other important trace elements appearing within the Montmorillonite.

     Call Joe for particulars (435) 313-2411       This email address is being protected from spambots. You need JavaScript enabled to view it.

     The Window Peak monument sitting atop the central point of the Panaca Montmorillonite deposit provides a “rock record” of the formation.  The harder material that has withstood the rigors of centuries of weathering is obviously of inferior quality for nutritional purposes.   Some twenty feet below the bottom of the monument is the finer, softer material, richer in humates and fulvates called Montmorillonite.  What remains visible, is essentially the overburden that is no longer found covering the areas of interest for present and future excavation.

     The old warm spring and swimming hole outside the city limits of Panaca, is still assisting the growth of some of the same rushes and lush pond grasses whose ancestors may have provided much of the organic material, interbedded in the silts now being harvested along with the Montmorillonite.

dissertation.  The dichotomy is certainly a provocative one in light of the balance of this presentation.  Nevertheless, there seem to be on the Web, nearly as many authoritative sources holding for the distinction, as there are neophyte opinions favoring the jumbled approach.More Uses
Bentonite as distinguished then, from Montmorillonite, on the basis of either a substantial Sodium or Calcium (from calcite, and gypsum) content, along with additional significant amounts of Iron ions and certain minerals such as feldspar and quartz, has in actuality different optimal uses.  It would seem that these mega-elements, as added ingredients, make Bentonite serve to be well-suited for:   
      a)    Use as a foundry sand, bleaching clay (Fuller's Earth), cleaning and filtering agent, an aid to effect water impedance, employment as an additive to ceramic materials, cement tiles, concrete, plaster, sheetrock and other forms of insulation, and agent in iron ore palletizing.
     b)    Providing colloidal benefits with application to such industries as cosmetics,  personal care products (suspending agent, gellant and binder), pharmaceutical, and household products (crayons, paste, shoe polish, paint thickener, etc.)
     c)    Water proofing and lubricating grease.
     d)    Additive in packaging and inks, and the making of jars, pails, drums, paper bags, copy paper, bulk bags and fiberboard containers, and
     e)    other such diverse and peculiar purposes including as an ingredient in cat litter, dynamite, and matches,
     One website suggests that commercial grade Bentonite may be represented as: SiO2= 61.3% and Al2O3= 19.8%,--quite different figures from the edible clay, Montmorillonite!Which would you rather eat?  
     There appears to be a consensus that both Bentonite and Montmorillonite have a vast array of properties and benefits with some cross-over into industrial and nutritional applications by both.  But given the preference by industry for Bentonite which would you rather eat?One “manufacturer” of Montmorillonite warns:Generally speaking, make sure the label on the clay you take says “Montmorillonite,” as Bentonites and other types of clay can contain overwhelming amounts of certain minerals that could pose potential danger to the system. Both Montmorillonite and Bentonite clays belong to the Smectite family,  …  however, Montmorillonite is purer, more complex clay with greater exchange capacities.  Its ability to adsorb and absorb toxins makes it the most preferred species of edible clay.   
     Furthermore, the method of preparation for market of Bentonite is vital.  An important study in Brazil indicated grinding was detrimental to Bentonite.
In addition to aggregation of the particles, large grinding times originated damage to the structure on the bentonite, interlayer collapse and Al-Mg remotion from octahedral sheet of near 30%. Nevertheless, the characteristic type of Montmorillonite remaining in the ground sample was preserved and the interlayer collapse was reversible after rehydration. Aggregation in thick particles reduced suspension viscosity.  
     With these views before us, two things come to mind:1)    If Bentonite is superior as an industrial agent, why waste valuable Montmorillonite to do what Bentonite does better?2)    If “pure” Montmorillonite is uniquely suited to assist agriculture and to benefit other organisms nutritionally, why would a serious formulator want to risk the effects of the added minerals that differentiate Bentonite?The intelligent approach would seem to be to use both minerals, respectively, for their strengths and not spend lots of money trying to eliminate some things from one, or adding them to the other.Back to Diatoms
The name diatom (pronounced “die-uh-tome”) comes from a Greek word diatomos that means “cut in half”, because the shells of diatoms have two overlapping, symmetrical halves.       The diatom is a member of Bacillariophyta found within the phylum of algae.
     There are something like 60,000 species of these algae presently known, but experts   estimate that there are more likely 10x – 100x this many unnamed species still being discovered.
 Diatoms are unicellular (single-celled) organisms that may live as individuals or survive more commonly in groups called colonies.  They still thrive in most all the waters of the Earth, both salt and fresh.  Diatoms form shells made out of the silica that they extract from the

     Enquirer (1818–20).  Noted writer and Democratic Party leader, Benton championed agrarian interests and westward expansion during his 30-year tenure as a US Senator.  As
the head of steamboat river navigation on the Missouri River, Fort Benton became a boomtown for gold seekers and cattlemen on their way to California.   []  It later rose to the prominence of a city, and became seat (1865) of Chouteau County.  Fort Benton’s location may be observed about 40 miles northeast of Great Falls, Montana (west central part of the State) at the confluence of highways 80 and 87 and the Missouri River.  By analogy, to stubbornly refer to Bentonite as “Montmorillonite”, “Taylorite” or “Pascalite” would be as ridiculous as persisting in referring to Fort Benton as “Fort Lewis”.

Over the course of modern history within the US geological discovery process, several other synonyms have been found for what is ostensibly Bentonite.  These include, along with the foregoing Montmorillonite epithets:  Calcium Bentonite, Sodium Bentonite, bentonite magma, Fuller's Earth, hectorite, hormite clay, saponite, southern bentonite, tixoton, volclay, volclay bentonite BC, wilkinite, and Wyoming Sodium Bentonite.   A number of these, such as saponite, have since been segregated from what most would agree to be distinctively Bentonite, but there is still a lot of confusion and misinformation about where to draw the line if at all, between Bentonite and Montmorillonite.  Notice Diatomite is not considered to be in synonymy with either, even though all three are related to “diatomaceous earths”.  The difference is that Diatomite is not a clay.

Chemical formulation, Geological Characteristics

     Diatomite in all of its forms, the Bentonites and the alternative Montmorillonoid classification for the broader group, aka Smectite clays, including specifically Montmorillonite, are composed largely of Silicon, once absorbed by diatoms, and originally deposited as sediment.  Some species of diatoms inhabited fresh water, and some in salt water, during different periods of geologic time. [Refer to separate section on diatoms at the conclusion of this article.]  The distinction between Diatomite and the Montmorillonoids is fairly simple.  Diatomite is a form of silica--like a common sand by the same name. Its scientific formula is SiO2 which is also the same basic formula for chert, flint, and common quartz.  However, Diatomite is usually more chalky, and often a fairly homogeneous material found in expansive deposits.  Its SiO2 cousins are more rock-like, and therefore much harder--the result of an extrusive volcanic formation, causing even smaller crystal size.  The diverse forms of Silicon Dioxide are a result of the impurities they contain.  They are mostly found in less impressive quantities than Diatomite, and typically occur in shattered veins, as opposed to sedimentary deposits.


     On the other hand, the Silicon absorbed by the species of diatoms making up Montmorillonite and the Bentonites was converted to a “silicate”, specifically an Aluminum silicate (Al SiO4)-4.  As the dead diatoms settled to the lake bottom, their remains became intermixed with considerable detrital material, including other mineral particles, and organic matter.  Hence, the sediment they formed became a powdery clay.  Shales eventually result from and revert to clay, cyclically. As shale eventually is left exposed due to the uplifting of strata during seismic activity, eventual break-up and degradation occurs through mass wasting, weathering, and biochemical interactions, once again contributing to the formation of clay.  If shale is trapped for longer periods under greater pressure, it undergoes a metamorphosis and becomes slate.  Much harder than shale, slate may contain the visible petrified outlines of the remains of animals much larger than diatoms making up its basic infrastructure.  But is ground up slate as effective as living clay in agricultural and nutritional applications?

Various formulae have been proposed for Bentonite, hence the term, “Bentonites.”  One formula for a granular Bentonite from Wyoming is given as:

(Al, Fe1, 6 7'Mg0,33), Si4 O10 (OH) 2Na+Ca++

     This particular clay is soft-gray in color, but does not necessarily represent even all of the Wyoming Bentonites, much less Bentonite, globally nor generically.  
     Some producers of Bentonite package it as a product rather than sell it as an ingredient to others, hence such brand-makers can also be called “manufacturers” in that context.  The labels “Sodium Bentonite” and “Calcium Bentonite” in fact, started out as marketing names for Smectite clay minerals from a particular area.  

     It is possible that some “manufacturers” tamper with the formulation of Bentonite by blending, or are not very explicit in stating their formulae, or perhaps are even careless in doing so, as the variety of formulae which follow, may suggest.  In one case the content of Aluminum is omitted which should raise an eyebrow.  
NaO5 Al25Si35O10(OH)2•(H2O)
(Na,Ca) (Al,Mg)6(Si4O10)3(OH)6-nH20
How could such diverse formulations all be Bentonite?  Conversely, with so many different expressions possible, how could anyone intelligently say that Bentonite and Montmorillonite were the same thing?
     What may be said of Bentonite and Montmorillonite is that we seem to have a problem of semantics fed by personal connotations.  If we can agree that the formula for that deposit of basic Montmorillonite, as first described in France, and later analyzed scientifically pursuant to our modern notions of chemistry and geology, can be rendered as:

Al2O3 – 4SiO – x H2O

then we could perhaps exclude the so-called Bentonites, yet admit to the fraternity of technical Montmorillonite that exotic variety claimed by Window Peak Trace Minerals, once formulated as:
MgO Al2O3 5SiO2 nH2O

This logic allows room for a variety of Bentonites to co-exist, and yet be distinguished from Montmorillonite. This would seem to be a sensible approach rather than throwing our hands up in the air and acquiescing that Bentonite is simply the generic name for a whole bunch of “ites”.  Now that we have begun to reconcile a rather confusing pedigree with current geological understanding from marketing practices, how is Bentonite recovered?

Where is Bentonite proper, found?
Bentonite minerals occur as seams or lenses containing up to 50% moisture.  Because deposits are rocklike in nature they are usually extracted by quarrying (opencast mining).
We are informed that most high-grade, commercial, “Sodium Bentonite” mined in the United States, comes from the area between the Black Hills of South Dakota and the Big Horn Basin of Montana.

A great website for the geography of other such locations is: (This author found only one ambiguous entry, i.e., while the holotype referenced therein evidently came from Wyoming and is referred to as a Fort Benton Shale, one should not infer that Fort Benton is also in Wyoming, but rather recognize that it is in fact in Montana, as previously set forth herein.)

Thus, we see Bentonite as a rather common mineral complex occurring all over the world and at many locations in each of States within the continental USA.  “Calcium Bentonite” is supposedly even more common than the “Sodium Bentonite” variety.  Further, we might infer that a number of the historical locations for Bentonite more accurately were actually for Montmorillonite, and vice versa.

     Historical perpetuation of the apparent confusion seems to have been rampant.  Nevertheless, if a true distinction can be made should we assume Montmorillonite to be any less common?  This author believes that answer to be a resounding, “Yes”.  If we are able to segregate out the Montmorillonites from the broader  group called Bentonites with any kind of consensus, then and only then can we prove this hypothesis.  Another challenge would be to further attempt to grade known deposits according to fresh water formations and those formed under the influence of salt water.  Famous minerals such as limestone and dolomite were definitely formed in shallow marine environments and are much older than the Montmorillonoids.

Alas, such an exercise is not within the scope of undertaking the clarification attempted herein, and the writer leaves it to more highly trained chemists, geologists with the USGS and university professors, professional metallurgists, soil scientists, and the like.  The hypothesis that the two varieties of clay can be more articulately segregated once and for all, satisfying a globally-accepted objective standard, might be the basis for some future

For more info call Joe at 435 313 2411  




A  Clay
Bentonite  is a member of the Smectite clay family which is one of seven major clay groupings, and Smectite is further subdivided into seven sub-groupings of its own.   Clays are classified amongst known colloids.  By definition clays are fine-grained sediments less than 0.0039 mm in size.   Smectite’s general chemical formula is:


     [Ca, Na, H) (Al, Mg, Fe, Zn) 2(Si, Al) 4O10(OH)2 - xH2O]


     Usually, Bentonite is comprised of about 80% Montmorillonite, another member of the Smectite Group, along with minor amounts of Smectite’s additional five other prominent members.  In alphabetical order they are: Nontronite, Pyrophyllite, Saponite, Sauconite, and Talc.   All members of the Smectite Group are 2:1 clays, meaning they are composed  principally of three-layers consisting of two tetrahedral sheets for every one octahedral sheet.   They are hydrophilous; Aluminum phyllo-silicates with a crystalline form.


     Oil Well Drilling   Bentonite is most commonly known for its use as a major component of drilling mud, particularly for oil wells, but is also widely used as an additive for viscosity and filtration control.  When exposed to water, Bentonite, characteristic of all clays, swells considerably, making it ideal for protecting subterranean formations from invasion by the other drilling fluids making up the mud by providing a thixotrophic effect.  However, it is mainly used as circulation mud in rotary drilling systems.  Bentonite’s chief purpose as a drilling mud is to lubricate and to cool the cutting bits, to carry away cut rock fragments, and to act as a seal against the escape of gas from the bore hole.  Other related functions of such Bentonite based fluids is to prevent the hole from blowing out, as well as, to condition the wall of the drill hole to prevent caving-in.  


     Its major component, Montmorillonite forms when basic rocks, such as tuff or volcanic ash in fresh water calderas and shallow marine environments, are altered.  This process is known as devitrification and comprehends a chemical change of such glassy igneous material. Although Bentonite contains prodigious amounts of its sister clay, Montmorillonite, Bentonite is much superior for drilling because it is often enriched with an usually high sodium content.  Hence the name “Sodium Montmorillonite”, or (Na) Montmorillonite.  


     Another form of Bentonite, “Calcium Montmorillonite” or (Ca) Montmorillonite is deemed to be inferior for this purpose.  Calcium Montmorillonite requires additives such as Sodium Carbonate, long-chain synthetic polymers, carboxymethylcellulose (CMC), polyphosphates, or starch to be injected in order to help make the final product meet quality specifications as a drilling mud.  Unfortunately, these ingredients may not remain effective in the long-term when in use on a drilling rig, due to bacterial attack, high temperature, mechanical shear-degradation, hardness ions in the water, and other factors that can render such additives ineffective.
Originally, the Smectite Group was better known as the Montmorillonite Group, hence Bentonite, Saponite, Talc, etc., may be called “Montmorillonoids”.   For additional background concerning Bentonite and its sister clays, consult the website hosted by Window Peak Trace Minerals, an important supplier of Montmorillonite for application in agriculture, and animal and human nutrition.


     Historical sketch of Certain Smectite Clays’ Nomenclature
Despite what you may read on other websites, Bentonite and Montmorillonite, are not exactly the same thing.  Montmorillonite was a name coined in 1847 for a discovery near the Prefecture of Montmorillon (départment of Vienne in the region of Poitou-Charentes), France.  [Mauduyt: Un mot sur un morceau de quartz d´une variété particulière, ainsi que sur une substance minérale trouvée dans le department de la Vienne. Bull Soc Géol France 4 (1847) 168-170].  Mauduyt’s chosen name for the mineral, “Montmorillonniste” was short-lived. Monsieurs Damour and Salvetat suggestion of the label “Montmorillonite” has stuck ever since.
     Bentonite proper (aka “Pascalite”, was first discovered in 1830 by the French-Canadian fur trapper Emile Pascal atop the 8600 feet high Big Horn Mountains in Wyoming, but was not distinguished from the former until much later.  Pascal soon developed a mining partnership with Ray Pendergraft calling the clay after himself.  By the late 1880s William Taylor became the biggest producer of this variety of Smectite in the Rock Creek area of Wyoming, and the common name “Taylorite” was born in his honor.  However, it was just before the turn of the 20th Century that American geologist W. C. Knight devised the name Bentonite [Eng Min J (1898) 66: 491] for a deposit he found near Fort Benton, Montana --a portion of the Fort Benton Formation geological stratum that extends into the Rock Creek area of eastern Wyoming.  Pascalite and Taylorite, along with many other names, long since have fallen into synonymy with Bentonite, the preferred name by serious geologists.


     Interestingly enough, Fort Benton was originally called Fort Lewis (founded in 1846 as a well-known American Fur Company outpost by Major Alexander Culbertson, but was renamed in 1850 for Thomas Hart Benton.  After military service in the War of 1812, Benton settled in St. Louis, Missouri, and in 1815 and became editor of the St. Louis