Clinoptilolite is a natural

zeolite Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. These p ...

composed of a microporous arrangement of silica and alumina tetrahedra. It has the complex formula . It forms as white, green to reddish tabular

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ...

tectosilicate Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide, ) is usually consid ...

crystals with a

Mohs hardness The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by t ...

of 3.5 to 4 and a

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest ...

of 2.1 to 2.2. It commonly occurs as a

devitrification Devitrification is the process of crystallization in a formerly crystal-free (amorphous) glass. The term is derived from the Latin ''vitreus'', meaning ''glassy'' and '' transparent''. Devitrification in glass art Devitrification occurs in glass a ...

product of

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

glass shards in

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock ...

and as vesicle fillings in

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predo ...

s and rhyolites. It was described in 1969 from an occurrence in the Barstow Formation,

San Bernardino County San Bernardino County (), officially the County of San Bernardino, is a county located in the southern portion of the U.S. state of California, and is located within the Inland Empire area. As of the 2020 U.S. Census, the population was 2,181, ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

. Sodium levels in clinoptilolite are generally higher than potassium levels, as is the case with the San Bernardino Barstow Formation, but there are sources that are potassium-rich and have minimal sodium. It forms a series with

heulandite Heulandite is the name of a series of tecto-silicate minerals of the zeolite group. Prior to 1997, heulandite was recognized as a mineral species, but a reclassification in 1997 by the International Mineralogical Association changed it to a ser ...

: *Clinoptilolite-Ca – heulandite-Ca solid solution series *Clinoptilolite-K – heulandite-K solid solution series *Clinoptilolite-Na – heulandite-Na solid solution series Use of clinoptilolite in industry and academia focuses on its

ion exchange Ion exchange is a reversible interchange of one kind of ion present in an insoluble solid with another of like charge present in a solution surrounding the solid with the reaction being used especially for softening or making water demineralised, ...

properties having a strong exchange affinity for ammonium ( NH₄⁺). A typical example of this is in its use as an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

-based

urea Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important ...

sensor. The name is derived from the Greek words (κλίνω; "oblique"), (φτερών; "feather"), and (λίθος; "stone").

Use

Clinoptilolite has many applications due to its effect as a

molecular sieve A molecular sieve is a material with pores (very small holes) of uniform size. These pore diameters are similar in size to small molecules, and thus large molecules cannot enter or be adsorbed, while smaller molecules can. As a mixture of molecu ...

, among others as an additive for building materials, as aggregate in horticulture, as an additive to cattle feed, as an additive in household products, as a desiccant, and in environmental technology. Clinoptilolite was used on a large scale in the nuclear disaster of Chernobyl. There, the mineral was used on the one hand as an ion exchanger in cleaning plants to treat radioactively contaminated wastewater. On the other hand, it was added to cattle feed in order to bind and eliminate radioactive cations such as ¹³⁷

cesium Caesium (IUPAC spelling) (or cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only five elemental metals that ar ...

as an ion exchanger in the digestive tract.Institut für Geologie der Uni Bern: ''Zeolithe – Entstehung und Vorkommen. Fallbeispiel Tschernobyl''
(PDF, 7 MB) Clinoptilolite is marketed within the EU as medical product and is associated with scientifically unproven healing effects. It is not approved as a

food supplement A dietary supplement is a manufactured product intended to supplement one's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in order ...

for human use due to the Novel Food Regulation. In Germany, it was therefore registered in December 2011 by the Federal Office of Consumer Protection and Food Safety under the rapid alert number "2011/1849" as an unauthorized novel food ingredient in food supplements.Pharmazeutische Zeitung online: ''Klinoptilolith. Remedy or humbug?''
/ref> Clinoptinolite of sedimentary origin may be used as a "technological" additive in animal feed. It then has the function of binder. The European Commission authorized clinoptinolite in animal nutrition for all animal species in 2013.Commission Implementing Regulation (EU). No 651/2013 of 9 July 2013''
/ref> Only clinoptinolite of sedimentary origin is allowed.

References

External links

Mineral galleriesClinoptilolite Zeolite Applications
Sodium minerals Potassium minerals Calcium minerals Aluminium minerals Zeolites Monoclinic minerals Minerals in space group 12 {{silicate-mineral-stub

Use

See also

References

External links