Chemical Properties
Saponite is a naturally occurring 2:1 phyllosilicate clay of the
smectite (montmorillonite) group. It is a magnesium-rich hydrated
aluminum silicate and is present as a component of some
commercial magnesium aluminum silicate clays. It occurs in soft,
amorphous masses in the cavities of certain rocks.
Saponite occurs as a white to off-white, dull powder composed
of fine-grained crystals of colloidal size. The material is greasy or
soapy to the touch and swells on the addition of water.
Production Methods
Naturally occurring saponite is mined from deposits in various
localities around the world.
Agricultural Uses
Saponite is an example of smectite, a 2:l clay mineral.
This 2:l layer has aluminum octahedral sheets
sandwiched between two silicon tetrahedral sheets to
make a unit cell. In saponite, all the octahedral holes are
filled with magnesium ions and 15 to 20% of the
tetrahedral holes are filled with aluminum ions. The rest
of the holes are filled with silicon.
Pharmaceutical Applications
Saponite is a colloidal material present in various naturally
occurring clays such as magnesium aluminum silicates and is
therefore suitable for use in pharmaceutical formulation applications
as an adsorbent, viscosity-increasing agent, suspending agent,
or as an oil-in-water emulsifying agent.
Saponite, as a component of magnesium aluminium silicates, is
useful as a formulation component in semisolid cosmetic and health
care products.
Safety
Saponite is a natural clay mineral that is not acutely toxic; therefore,
no toxicity values have been established. However, it may contain
small amounts of crystalline silica in the form of quartz. Chronic
exposure to crystalline silica can have adverse effects on the
respiratory system. EU labeling states the material is not classified as
dangerous.
Saponite dust can be irritating to the respiratory tract and eyes.
Contact with this material may cause drying of the skin.
storage
Saponite is a stable material and should be stored in a cool, dry
place.
Incompatibilities
May generate heat in contact with hydrofluoric acid.
Regulatory Status
Reported in the EPA TSCA Inventory.
