Bentonite and Montmorillonite clays often interchange names and have
similar properties yet vary from deposit to deposit. This commonality
can be confusing when first learning about clays.
Actually it is not a significant
difference. They are both Smectites. Most Smectite clays have
Montmorillonite properties. The Montmorillonite name was actually
given to a Smectite clay that was found in the Montmorillon area of
France. Clays are often named after their location. Bentonite was
originally named for Smectite clay found near Fort Benton
Wyoming. Most Smectites are now
referred to as Bentonites or Montmorillonites. Like Kleenex was the
only tissue for so long that most everyone says, ‘Please hand me a
Kleenex,’ instead of a tissue or by another brand name.
There are very few true 100%
Montmorillonite clays. Some Montmorillonite properties are found in
different percentages in most clays. It has become a buzz word by
association. It is often found in your Bentonites but also in Illites,
Kaolins and Chlorites as well, all to different degrees.
Below are several references where
Bentonite and Montmorillonite are used interchangeably.
This is a definition from
Montmorillonite is a very soft
phyllosilicate mineral that typically forms in microscopic crystals,
forming a clay. It is named after Montmorillon in France.
Montmorillonite, a member of the Smectite family, is a 2:1 clay,
meaning that it has 2 tetrahedral sheets sandwiching a central
octahedral sheet. The particles are plate-shaped with an average
diameter of approximately 1 micrometre. It is the main constituent of
the volcanic ash weathering product, Bentonite.
Montmorillonite and Bentonite's water
content is variable and it increases greatly in volume when the
absorbs water. Chemically Montmorillonite is hydrated sodium calcium
aluminum magnesium silicate hydroxide
(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2·nH2O. Potassium, iron, and
other cations are common substitutes; the exact ratio of cations
varies with source. It often occurs intermixed with chlorite,
muscovite, illite, cookeite and kaolinite.
“Bentonite, also referred to as
Montmorillonite, is one of the most effective and powerful healing
clays used to treat both internal and external maladies.”
consists of nanometer scale of Smectite clay minerals (mainly
Montmorillonite) and micrometer scale of macro-grains (mainly quartz).
Properties of saturated Bentonite are characterized by hydrated clay
is a dark-grey to dark-green clay-rich rock composed of mostly
Montmorillonite, with minor concentrations of cristobalite, zeolite,
and quartz, among others.”
Some other interlacing names are mentioned in
“BENTONITE and FULLER'S EARTH are the two
important naturally occurring clays of great commercial importance
possessing inherent bleaching properties. They are, therefore commonly
called bleaching clays. They fall mainly under Montmorillonite group
containing a varying amount of attapulgite.”
Bentonite and Montmorillonite have
similar mineral properties. The most important of which are
attributed to the Smectite Family of clays. The Cation Exchange
Capacity CEC and the Specific Surface area of Smectites are
considerable larger than other families of clays being as they are
predominately 2:1 clays. There absorption capacity is as much as 8
times greater than other clays. (Surfacing Mining, 2nd
Edition, by B. A. Kennedy.)
All clays are natural unless they have
been processed or tampered with by man. Most clays are evolved from
volcanic ash that has weathered for millions of years therefore they
qualify as natural. Pure refers to the cleanliness of the deposit.
The surface clays most likely have been exposed to pollutants and
fecal contamination. That is why you want a subsurface deep deposit of
the clay. Look for clay that has a Microbial Lab Test Report.
Green clay is also a popular term and can
be a Montmorillonite or a Bentonite. Historically green clays have
been known to be the most popular healing clays and are predominately
of the Bentonite or Montmorillonite clays, though they can be from
other families as well. Green clays are generally from marine life
from lakes or inland seas or rivers that the volcanic ash was
According to Surface Mining, 2nd
Edition by B. A. Kennedy, Bentonite is clay consisting essentially of
Smectite minerals. The term Smectite is applied as a group or family
name and Montmorillonite is a mineral species name.
So, in answer to the question, are
Montmorillonite and Bentonite the same? No not specifically. Are
they similar in properties and abilities? Yes. Are they used
interchangeably and synonymously? Yes.
And that’s all I have to say about that
Perry A~ is the
Living Clay: Nature’s Own Miracle Cure. She is dedicated to
spreading the word about clay’s healing benefits and putting the spot
light on safe healing with clay.