Clinoptilolite is a natural

zeolite Zeolites are a group of several microporous, crystalline aluminosilicate minerals commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a meta ...

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 Vector (geometric), vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in t ...

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, the crystalline forms of silica (silicon dio ...

crystals with a

Mohs hardness The Mohs scale ( ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fair ...

of 3.5 to 4 and a

specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

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 ...

product of

volcanic A volcano is commonly defined as a vent or fissure 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 fo ...

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 co ...

and as vesicle fillings in

basalt Basalt (; ) is an aphanite, 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 planetary surface, surface of a terrestrial ...

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 predomina ...

s and

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matri ...

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

San Bernardino County San Bernardino County ( ), officially the County of San Bernardino and sometimes abbreviated as S.B. County, 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 th ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. 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 tectosilicate 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 seri ...

: *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 species of ion present in an insoluble solid with another of like charge present in a solution surrounding the solid. Ion exchange is used in softening or demineralizing of water, purification of ch ...

properties having a strong exchange affinity for

ammonium Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) polyatomic ion, molecular ion with the chemical formula or . It is formed by the protonation, addition of a proton (a hydrogen nucleu ...

( NH₄⁺). A typical example of this is in its use as an

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

-based

urea Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...

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 of uniform size comparable to that of individual molecules, linking the interior of the solid to its exterior. These materials embody the molecular sieve effect, in which molecules larger than the pore ...

, 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; also spelled cesium in American English) is a chemical element; it has 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 ...

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 a person'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 ( ...

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

{{reflist 10. Kautsky, Mark. June 1984. ''Sorption of Cesium and Strontium by Arid Region Desert Soil''. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, Mackay School of Mines, University of Nevada, Reno.

External links

Mineral galleriesClinoptilolite Zeolite Applications
Sodium minerals Potassium minerals Calcium minerals Aluminium minerals Zeolites Monoclinic minerals Minerals in space group 12

Use

See also

References

External links