Clinoptilolite
| Clinoptilolite | |
|---|---|
 (size: 4.3 × 2.2 × 2.0 cm) |
|
| General and classification | |
| chemical formula |
|
|
Mineral class (and possibly department) |
Framework silicates (tectosilicates) - zeolite group - leaf zeolite |
|
System no. to Strunz and to Dana |
9.GE.05 ( 8th edition : VIII / J.23) 77.01.04.02 (K), 77.01.04.02a (Na) and 77.01.04.02b (Ca) |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | C 2 / m (No. 12) |
| Lattice parameters | see crystal structure |
| Formula units | Z = 1 |
| Physical Properties | |
| Mohs hardness | 3.5 to 4 |
| Density (g / cm 3 ) | 2.1 to 2.2 |
| Cleavage | completely after {110} |
| Break ; Tenacity | uneven |
| colour | colorless, white |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.476 to 1.491 n β = 1.479 to 1.493 n γ = 1.479 to 1.497 |
| Birefringence | δ = 0.003 to 0.006 |
| Optical character | alternating biaxially |
| Axis angle | 2V = 31 to 48 ° (measured) |
| Other properties | |
| Special features | Molecular sieve |
Clinoptilolite is the collective name for a group of unspecified minerals from the group of zeolites within the mineral class of " silicates and germanates ". These are the end links of a seamless mixed series with the following idealized compositions:
- Clinoptilolite-Ca : Ca 3 (Si 30 Al 6 ) O 72 · 20H 2 O
- Clinoptilolite-K : K 6 (Si 30 Al 6 ) O 72 · 20H 2 O
- Clinoptilolite Na : Na 6 (Si 30 Al 6 ) O 72 · 20H 2 O
From a chemical point of view, they are therefore hydrous aluminosilicates with calcium , potassium or sodium as connecting cations . All clinoptilolites crystallize in the monoclinic crystal system and structurally belong to the framework silicates .
Clinoptilolites mostly develop tabular crystals , but also occur in the form of fine-grained to massive mineral aggregates . In their pure form, clinoptilolites are colorless and transparent. However, due to multiple refraction due to lattice construction defects or polycrystalline training, they can also appear white and, due to foreign admixtures, take on a yellowish-white to reddish-white color, the transparency decreasing accordingly.
The group of clinoptilolites is one of the most common zeolites and plays an important industrial role.
Etymology and history
Clinoptilolite was named in reference to the related mineral Ptilolite ( mordenite ) and its inclined or inclined axis position in contrast to this after the Greek word κλίνειν [klinein] for tend .
Clinoptilolite was first discovered on Hoodoo Mountain in Park County (Wyoming) in the United States of America (USA) and described in 1923 by Waldemar Theodore Schaller . Since later, more precise analyzes found that clinoptilolite was not a single mineral, but a mixed series with very closely related end links, this was redefined in 1997/98 and in the course of a general revision of the zeolite nomenclature by Douglas S. Coombs et al. referred to as clinoptilolite-Ca, clinoptilolite-K and clinoptilolite-Na.
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , clinoptilolite-Ca, clinoptilolite-K and clinoptilolite-Na belonged to the general division of "tectosilicates (tectosilicates), with zeolites", where they together with Barrerit , Brewsterit-Ba , Brewsterit-Sr , Epistilbit , Goosecreekit , Heulandit-Ba , Heulandit-Ca , Heulandit-K , Heulandit-Na , Heulandit-Sr , Stellerit , Stilbit-Ca and Stilbit-Na the group of "Leaf Zeolites I" with the system no . VIII / J.23 formed.
The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), classifies clinoptilolite-Ca, clinoptilolite-K and clinoptilolite-Na in the more finely subdivided section of "tectosilicates" with zeolitic H 2 O; Family of zeolites ”. This is, however, further subdivided according to the type of scaffolding, so that the minerals can be found according to their structure in the subsection "Tables with 4-4-1-1 structural units", where they only belong to the unnamed group 9.GE together with the Heulandites .05 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns clinoptilolite-Ca, clinoptilolite-K and clinoptilolite-Na to the class of "silicates and germanates" and there in the department of "framework silicates: zeolite group". Here they are together with the Heulandites, the Stilbites as well as Barrerite and Stellerite in the group " Heulandite and related species " with the system no. 77.01.04 to be found in the sub-section of "Real Zeolites".
Education and Locations
Clinoptilolite is of sedimentary origin and is primarily formed from volcanic deposits such as tuff or volcanic glass. More rarely, clinoptilolite is also observed in cavities in other volcanic rocks, u. a. Basalts, andesites or rhyolites.
Significant locations of clinoptilolite can be found in the Ukraine, Australia, China and the USA, where they are also of great economic interest. Local occurrences of clinoptilolite can be found u. a. on Vogelsberg , in Franconia and in Styria .
Clinoptilolite Ca from Cape Lookout (Oregon) , Tillamook County, Oregon, USA (size of the upper aggregate ~ 1¼ mm)
Clinoptilolite-K from the Poudrette quarry, Mont Saint-Hilaire , Canada (field of view: 1.6 × 1.3 mm)
Clinoptilolite Na from Rodalquilar , Almería, Andalusia, Spain (field of view: 2.5 mm)
Clinoptilolite and mordenite (very fine, tufted fibers) from Succor Creek, Malheur Co., Oregon, USA (size: 5.5 × 3.7 cm)
Crystal structure
All end links of the clinoptiolite series crystallize monoclinically in the space group C 2 / m (space group no.12) , but differ slightly in their lattice parameters :
- Clinoptilolite-Ca: a = 17.66 Å ; b = 17.96 Å; c = 7.40 Å and β = 116.5 °
- Clinoptilolite-K: a = 17.69 Å ; b = 17.90 Å; c = 7.41 Å and β = 116.5 °
- Clinoptilolite Na: a = 17.63 Å ; b = 17.95 Å; c = 7.40 Å and β = 116.3 °
with one formula unit per unit cell .
use
Due to its effect as a molecular sieve, clinoptilolite has many areas of application, including as an additive for building materials, as an additive 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 during the Chernobyl nuclear disaster . There the mineral was used on the one hand as an ion exchanger in cleaning systems with which radioactively contaminated wastewater was treated. On the other hand, clinoptilolite was added to cattle feed to act as an ion exchanger in the digestive area to bind and excrete radioactive cations such as 137 cesium .
Clinoptilolite is sold within the EU as a medical product and linked to scientifically unproven medicinal effects. It is not approved as a dietary supplement due to the Novel Food Regulation. Clinoptilolite was therefore registered in December 2011 by the Federal Office for Consumer Protection and Food Safety (BVL) under the quick warning number “2011/1849” as a non-approved novel food ingredient in food supplements.
See also
literature
- Clinoptilolite , in: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 84.3 kB )
Web links
- Mineral atlas: clinoptilolite (mineral group) or clinoptilolite-Ca , clinoptilolite-K and clinoptilolite-Na
- Mindat: Clinoptiolite or Clinoptiolite-Ca , Clinoptiolite-K and Clinoptiolite-Na
- Webmineral: Clinoptilolite-Ca , Clinoptilolite-K and Clinoptilolite-Na
- Susterra Magazin - Clinoptilolite in horticulture
Individual evidence
- ↑ a b c d e Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 707 .
- ↑ a b c Clinoptiolite
- ↑ a b c IMA / CNMNC List of Mineral Names - Clinoptilolite-Ca, Clinoptilolite-K, Clinoptilolite-Na (PDF; 8.9 MB)
- ^ Waldemar T. Schaller: The Mordenite-Ptilolite group; Clinoptilolite, a new species , In: American Mineralogist , Volume 17 (No. 4, 1932), pp. 128-134 ( PDF 374.7 kB )
- ↑ Douglas S. Coombs, Alberto Alberti, Thomas Armbruster, Gilberto Artioli, Carmine Colella, Ermanno Galli, Joel D. Grice, Friedrich Liebau, Joseph A. Mandarino, Hideo Minato, Ernest H. Nickel, Elio Passengeria, Donald R. Peacor, Simona Quartieri, Romano Rinaldi, Malcolm Ross, Richard A. Sheppard, Ekkehart Tillmanns, Giovanna Vezzalini: Recommended nomenclature for zeolite minerals; report of the Subcommittee on Zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names , Mineralogical Magazine, Vol. 62 (No. 4, August 1998), pp. 533-571 ( brief description on minmag.geoscienceworld.org , last accessed on December 9, 2012)
- ^ Institute for Geology at the University of Bern: Zeolites - Origin and Occurrence. Case study Chernobyl (PDF, 7 MB)
- ^ Pharmaceutical newspaper online: Clinoptilolite. Cure or humbug?