Laumontite

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Laumontite
Laumontite-ck31aa.jpg
Laumontite from the "Himalaya Pegmatite" on Gem Hill , San Diego County , California (size: 4.5 cm × 3 cm × 2.3 cm)
General and classification
other names
  • Lomonite
  • Laumonite
  • Leonhardite
chemical formula Ca 4 [Al 8 Si 16 O 48 ] • 18H 2 O
Mineral class
(and possibly department) 		Silicates and Germanates - framework silicates
System no. to Strunz
and to Dana 		09.GB.10 ( 8th edition : VIII / F.11, appendix)
77.01.01.04
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Room group (no.) C 2 / m (No. 12) (No. 12) Template: room group / 12
Lattice parameters a  = 14.845 (9)  Å ; b  = 13.167 (2) Å; c  = 7.5414 (8) Å
β  = 110.34 (2) °
Formula units Z  = 1
Frequent crystal faces {110}, {20 1 }, stripes according to [001]
Twinning after {100}
Physical Properties
Mohs hardness 3 to 4
Density (g / cm 3 ) measured: 2.23 to 2.41; calculated: 2.306
Cleavage completely according to {010} and {110}
Break ; Tenacity uneven to shell-like; brittle
colour colorless, white to gray, pink, yellowish, brownish to golden brown
Line color White
transparency transparent to translucent
shine Glass luster, pearlescent luster on the gap surfaces
Crystal optics
Refractive indices n α  = 1.502 (leonhardite) to 1.514 (laumontite)
n β  = 1.512 (leonhardite ) to 1.522 (laumontite)
n γ  = 1.514 (leonhardite) to 1.525 (laumontite)
Birefringence δ = 0.012 to 0.013
Optical character biaxial negative
Axis angle 2V = * Laumontite: 33 ° to 47 ° (measured); 34 to 44 ° (calculated)
  • Leonhardite: 26 ° to 44 °
Other properties
Chemical behavior soluble in dilute hydrochloric acid , melts before the soldering tube
Special features white fluorescence under UV light

The mineral laumontite is a frequently occurring tectosilicate from the group of zeolites . It crystallizes with monoclinic symmetry and has the composition Ca 4 [Al 8 Si 16 O 48 ] · 18H 2 O. From a chemical point of view, it is a water-containing calcium aluminosilicate.

Laumontite usually develops prismatic to columnar crystals with a square cross-section, but is also found in the form of radial, fibrous and massive mineral aggregates . In its pure and unweathered form it is colorless and transparent. Due to the multiple refraction of light due to polycrystalline formation and the loss of crystal water ( dehydration ), it can also appear white and, due to foreign admixtures, take on a gray, pink, yellowish or brownish to golden brown color, whereby the transparency decreases accordingly.

Etymology and history

Laumontite was first discovered in 1785 by the French mineralogist Gillet de Laumont (1747–1834) in a lead mine near the French community of Huelgoat (Brittany). Described and named the mineral in 1803 by was Abraham Gottlob Werner after its discoverer, but first in the spelling Lomonit to the French pronunciation onomatopoeic play. In 1805 Robert Jameson adopted Werner's description and name in his System of Mineralogy .

In 1809, René-Just Haüy changed the spelling of the mineral name again to laumonite , until finally Karl Caesar von Leonhard coined the spelling laumontite, which is still valid today, in 1821.

classification

Already in the outdated 8th edition of the mineral classification according to Strunz , the laumontite belonged to the class of "silicates and germanates" and there to the department of "tectosilicates", where it was added to the " Dachiardite - Mordenite group " belonging to the zeolite family “With the system no. VIII / F.11 and the additional member ferrierite .

In the last revised and updated Lapis mineral directory by Stefan Weiß in 2018 , which, out of consideration for private collectors and institutional collections, is still based on this classic system of Karl Hugo Strunz , the mineral was given the system and mineral number. VIII / J.22-50 . In the "Lapis Classification" this also corresponds to the "framework silicates" department where Laumontit with boggsite , Dachiardit-Ca , Dachiardit-Na , Direnzoit , Edingtonit , ferrierite K , ferrierite Mg , ferrierite-Na , Gottardiit , mordenite, Mutinaite and Terranovaite form an independent group that also belongs to the zeolite family, but is unnamed.

The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and was updated by the International Mineralogical Association (IMA) until 2009, classifies the laumontite in the more finely subdivided section of “tectosilicates with zeolitic H 2 O; Family of zeolites ”. This is also further subdivided according to the crystal structure, so that the mineral can be found according to its structure in the subsection "Chains of simply connected rings of four", where it is the only member of the unnamed group 9.GB.10 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns laumontite to the class of "silicates and germanates" and there in the department of "structural silicates: zeolite group". Here it is together with Analcim, Hsianghualith , Pollucit and Wairakit in the group "Analcim and allied species" with the system no. 77.01.01 to be found in the subsection " Real Zeolites ".

Chemism

Laumontite is a hydrous calcium - aluminum - silicate having the composition Ca 4 [Al 8 Si 16 O 48 ] · 18H 2 O. The composition of the Alumosilikatgerüstes hardly varies. Small amounts of aluminum can become through Fe 3+ , which gives the laumontite a golden brown color.

The water content varies greatly with humidity, temperature and pressure and Laumontit already dehydrates in several stages at room temperature. At ~ 25 ° C, the water content drops continuously with decreasing relative humidity from 18 H 2 O pfu (100% rel. Humidity) to 16 H 2 O pfu at 80%. This is the water content, which in the older literature before 1992 is given as the water content of laumontite. In the range of 70 to 60% relative humidity, the water content drops sharply to ~ 14 H 2 O pfu, which corresponds to the composition of the leonhardite variety. In this transition area, leonhardite and laumontite occur together. Further, continuous dewatering only takes place under very dry conditions. From 10 - 0% relative humidity, the water content of leonhardite drops to ~ 12 H 2 O pfu. Launontit can be completely dehydrated by heating.

Calcium (Ca 2+ ) can be completely replaced by sodium and potassium . This occurs mainly without changing the aluminum and silicon content due to the exchange reactions

  • Ca 2+ + H 2 O = 2 Na +
  • Ca 2+ + H 2 O = 2 K +

In the Ca-Na mixture series, there is complete miscibility, while on the potassium side there is an extensive mixture gap of ~ 50 mol% K-Leonhardite up to the pure K-end link.

When potassium and sodium are incorporated together, these cations are incorporated into the structural channels in a strictly ordered manner. Sodium replaces calcium in its lattice position and potassium displaces a water molecule:

  • Ca 2+ + H 2 O = Na + + K +

To a lesser extent, sodium can also be incorporated through a coupled substitution of aluminum with silicon:

  • Ca 2+ + Al 3+ = Na + + Si 4+

Crystal structure

Laumontit cage:, view along the c-axis
Laumontite cage:, view roughly along the b-axis

Laumontite crystallizes monoclinically in the space group C 2 / m (space group no. 12) with the lattice parameters a  = 14.845  Å ; b  = 13.167 Å; c  = 7.5414 Å and β = 110.34 ° as well as 1 formula unit with 48 oxygen per unit cell . Template: room group / 12

Silicon (Si) and aluminum (Al) are tetrahedrally surrounded by 4 oxygen. These Si / AlO 4 tetrahedra are connected by all 4 oxygen at the corners to form a framework made up of rings of four, six and ten. The distribution of Al and Si to the tetrahedron positions is strictly ordered and there are two types of four-ring rings: rings made up of four SiO 4 tetrahedra and rings in which SiO 4 and AlO 4 tetrahedra alternate.

This aluminosilicate framework encloses cavities, which are enclosed by 8 rings of four, eight rings of six and two rings of tens (area symbol: [4 8 6 8 10 2 ]) and can store particles with a diameter of up to 6Å. These caverns are connected by common 10 rings in the direction of the c-axis ([001]). They form a one-dimensional channel system (Poor symbol: {1 [4 8 6 8 10 2 ] [001] (10-ring)}), which allows the passage of particles with a maximum diameter of ~ 4 Å.

Calcium (Ca) lies on the inside of these caverns and is surrounded on the one hand by the oxygen from the Al tetrahedron of the framework and on the other hand by the oxygen from the water molecules in positions W8 and W2 in the channels. The other water molecules in positions W1 and W5 are in the central area of ​​the channels and are only connected to the aluminosilicate framework and other water molecules via hydrogen bonds .

properties

Laumontite gives off part of its crystalline water over time in a dry environment and should therefore be stored in airtight containers. The transition from laumontite with 16-18 H 2 O per formula unit (pfu) to leonhardite with 13-14 H 2 O pfu is associated with a sudden change in the physical properties. The refraction of light decreases from 1.514 to 1.525 to 1.502 to 1.514 and the extinction angle, the angle between the crystallographic c-axis and the orientation of the polarizers in the polarizing microscope, when the crystal appears dark, changes from ~ 10 ° for laumontite to ~ 35– 50 ° at Leonhardit. This makes it possible to follow the water absorption of leonhardite under a polarizing microscope.

The uptake and release of water is associated with a change in the molar volume of ~ 2-3%. This leads to mechanical stresses, especially with larger crystals. Dehydrated laumontite is therefore brittle and can disintegrate even under low mechanical stress. The crystal structure survives this undamaged and can completely absorb the water again when it cools down or when water is supplied.

The cations (Ca, Na, K) embedded in the pore spaces of the aluminosilicate framework are exchangeable and laumontite can be used as an ion exchanger .

Modifications and varieties

As leonhardite an opaque by partial loss of water and white is tarnished variety of Laumontit named. It was named in 1843 by Johann Reinhard Blum in honor of Karl Cäsar von Leonhard (1779–1862). Leonhardite was listed as an independent mineral for a long time, until in 1997 the sub-committee for zeolites of the commission for new minerals, mineral names and classification revised the nomenclature of the zeolite group and determined that differences in water content are not a sufficient criterion for the definition of different zeolite minerals. Since then, leonhardite has been regarded as a variety of laumontite, although the transition from laumontite to leonhardite is associated with a sudden change in both the composition and the physical properties and, under certain conditions, both phases can coexist.

A variety of leonhardite rich in potassium and sodium was described by Fersman in 1908 as "Primary Leonhardite". This leonhardite contains ~ 14 H 2 O per formula unit (pfu) and does not absorb any further water. This is attributed to the high content of cations (~ 5.4 Ca + Na + K) in the structural channels. On the one hand, the excess cations occupy a position in the water; on the other hand, these ions in the channels hinder the passage of molecules and thus the absorption of water.

Surname T1 8 T2 8 T3 8 M 4 4 W1 4 W2 2 W5 8 W8 O 2- 48 annotation
Laumontite Si 4+ 16 Al 3+ 8 Ca 2+ 4 4 H 2 O 4 H 2 O 2 H 2 O 8 H 2 O O 48 fully hydrated laumontite
Leonhardite Si 4+ 16 Al 3+ 8 Ca 2+ 4 4 □ 4 H 2 O 2 H 2 O 8 H 2 O O 48 hypothetical end link
Si 4+ 16 Al 3+ 8 Ca 2+ 4 4 □ 4 H 2 O 2 □ 8 H 2 O O 48 hypothetical end link
Metal mount Si 4+ 16 Al 3+ 8 Ca 2+ 4 4 □ 4 □ 2 □ 8 □ O 48 synthetic, fully drained laumontite
Na-laumontite Si 4+ 16 Al 3+ 8 Na + 4 4 Na + 4 H 2 O 2 H 2 O 8 H 2 O O 48 hypothetical end link
Na-K-laumontite Si 4+ 16 Al 3+ 8 Na + 4 4 K + 4 H 2 O 2 H 2 O 8 H 2 O O 48 hypothetical end link, ~ 25 mol% in "Primary Leonhardite"

Education and Locations

Heulandite (pink), laumontite (white) and prehnite (green) from Passaic County , New Jersey (USA)
Almost 10 centimeters long laumontite crystal from the "Pine Creek Mine", Inyo County, California
Pseudomorphism from prehnite to laumontite from Mumbai , Maharashtra, India (size: 12.1 × 12.0 × 3.7 cm)

Laumontite is an important index mineral of the zeolite facies and is stable at temperatures between ~ 100 and 250–300 ° C. Which reactions lead to the formation and degradation of laumontite and the temperatures at which these reactions start depend heavily on the composition of the parent rock, in particular on the SiO 2 content and Ca / Na ratio. SiO 2 -undersaturated (basic) parent rocks with a high Ca / Na ratio, e.g. B. due to anorthite-rich feldspars, favor the formation of laumontite.

In the presence of water and quartz, and the absence of sodium to Laumontit forms bar at pressures below ~ 600 at 100-150 ° C from Stilbit :

  • Stilbit = laumontite + quartz + water.

Above 600 bar, laumontite is formed from heulandite at temperatures of 150–200 ° C via the reaction:

  • Heulandite = laumontite + quartz + water.

At temperatures above ~ 230 ° C / 500 bar to 300 ° C / 3000 bar, laumontite breaks down into wairakite :

  • Laumontite = wairakite + water

Below a line of 1 bar, ~ 150 ° C and 500 bar, ~ 230 ° C, laumontite is no longer stable and is degraded to yugawaralite :

  • Laumontite + quartz = Yugawaralite

The upper pressure stability of Laumontit is ~ 3000 bar. Laumontite is also mined to form lawsonite :

  • Laumontite = Lawsonite + quartz + water

The conversion of laumontite to the partially dehydrated variety leonhardite takes place along a line of 46 ° C / 1 bar and 235 ° C / 5 kbar. Accordingly, laumontite is always formed as leonhardite in its stability range of the zeolite facies and only hydrated retrograde to laumontite.

Like other zeolites, laumontite forms in fissures of basalt , andesite , granite or various metamorphic rocks . In addition, laumontite is also formed in hydrothermal, calcareous deposits. Other zeolites , but also apophyllites and chlorites , calcite , datolite , heulandite and / or stilbite can occur as accompanying minerals .

Laumontite has already been proven to be a frequent mineral formation at many sites, with around 1000 sites being known to date (as of 2013). In addition to its type locality Huelgoat, the mineral occurred in France so far at Cambo-les-Bains in Aquitaine, at Espira-de-l'Agly (municipality of Rivesaltes ) in Languedoc-Roussillon, at Arnave , Salau (Ariège) , Port-d'Agrès and in the Aure Valley in Midi-Pyrénées and at Saint-Michel-de-Chaillol in Provence-Alpes-Côte d'Azur.

The pits in the Pandulena Hills in India, where colorless and white, needle-like crystals of up to 38 centimeters in length emerged, are known for their extraordinary Laumontite finds. Also from India, more precisely from Poona and Mumbai are known pseudomorphs of Prehnit after Laumontit. At least up to 15 centimeters long crystals could be recovered in the "Pine Creek Mine" on Mount Morgan in Inyo County (California).

In Germany, laumontite was found in the Clara mine in Baden-Württemberg, in several places in the Bavarian Forest (Hauzenberg, Waldkirchen), near Bornberg / Herbornseelbach and Hochstädten (Bensheim) in Hesse, near Bad Harzburg and Sankt Andreasberg in Lower Saxony, on Clemensberg in North Rhine-Westphalia, near Baumholder , on Potschberg and Niederkirchen (West Palatinate) in Rhineland-Palatinate, on Petersberg near Halle in Saxony-Anhalt, in the mining company “Willi Agatz” in Saxony and near Weitisberga in Thuringia.

In Austria Laumontit was in many places in the Hohe Tauern and the Koralpe in Carinthia, on Mitterbach digging in the municipality Dunkelsteinerwald and in several places in Waldviertel in Lower Austria, in the Gastein Valley and Habachtal in Salzburg and in some places in Styria , Tyrol and Upper Austria found .

In Switzerland, the mineral has so far mainly occurred in the cantons of Graubünden (Albigna Glacier, Tujetsch), Ticino (Valle Maggia), Uri and Wallis (Binntal, Goms)

Other sites are found in Algeria, Antarctica, Argentina, Australia, Azerbaijan, Belgium, Brazil, Bulgaria, Chile, China, Costa Rica, Denmark, Ecuador, the Fiji Islands, Iceland, Indonesia, Iran, Italy, Japan, Canada , Kyrgyzstan, Cuba, Madagascar, Mexico, Namibia, New Zealand, Nicaragua, Norway, the Philippines, Poland, Puerto Rico, Réunion, Romania, Russia, Sweden, Slovakia, Spain, South Africa, Taiwan, Tanzania, Thailand, Czech Republic, Turkey, Ukraine, Hungary, United Kingdom (Great Britain) and United States of America (USA).

See also

literature

  • H. Bartl, KF Fischer: Investigation of the crystal structure of the zeolite laumontite . In: New yearbook for mineralogy, monthly books . 1967, p. 33-42 .
  • BM Madsen, KJ Murata: Occurrence of Laumontite in the Tertiary sandstones of the central Coast Ranges of California . In: USGS PP 700-D . 1970, p. 188-195 (English).
  • AB Thompson: Laumontite equilibria and the zeolite facies . In: American Journal of Science . tape 269 , 1970, pp. 267-275 (English).
  • Bruce E. Miller, Edward D. Ghent: Laumontite and barian-strontian heulandite from the Blairmore Group (Cretaceous), Alberta . In: The Canadian Mineralogist . tape 12 , 1973, p. 188–192 (English, rruff.info [PDF; 467 kB ; accessed on October 20, 2019]).
  • H. Bartl: Structure refinement of leonhardite, Ca [Al 2 Si 4 O 12 ] · 3H 2 O, by means of neutron diffraction . In: New yearbook for mineralogy, monthly books . 1990, p. 298-310 .
  • T. Armbruster, T. Kohler: reform and dehydration of laumontite: a single crystal X-ray study at 100K . In: New yearbook for mineralogy, monthly books . 1992, p. 385-397 (English).
  • 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 Passasslia, Donald R. Peacor, Simona Quartieri, Romano Rinaldi, Malcolm Ross, Richard A. Sheppard, Ekkehard 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 . In: The Canadian Mineralogist . tape 35 , 1997, pp. 1571–1606 (English, minsocam.org [PDF; 3.5 MB ; accessed on October 20, 2019]).
  • Y. Lee, JA Hriljac, T. Vogt: Pressure-induced migration of zeolitic water in laumontite . In: Physics and Chemistry of Minerals . tape 31 , 2004, p. 421-428 (English).

Web links

Commons : Laumontite  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e f g h Gilberto Artioli, Kenny Stahl: Fully hydrated laumontite: A structure study by flat-plate and capillary powder diffraction techniques . In: Zeolites . tape 13 , no. 4 , 1993, p. 249-255 , doi : 10.1016 / 0144-2449 (93) 90002-K (English).
  2. ↑ a b c d e Kenny Stahl, Gilberto Artioli: A neutron powder diffraction study of fully deuterated laumontite . In: European Journal of Mineralogy . tape 5 , no. 5 , 1993, p. 851-856 , doi : 10.1127 / ejm / 5/5/0851 (English).
  3. ^ David Barthelmy: Laumontite Mineral Data. In: webmineral.com. Retrieved October 20, 2019 .
  4. ^ Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  703 (English).
  5. ↑ Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p.  913 .
  6. ↑ a b Laumontite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 81  kB ; accessed on October 20, 2019]).
  7. ↑ a b c d e f g h i j k l DS Coombs: Cell size, optical properties and chemical composition of laumontite and leonhardite . In: American Mineralogist . tape 37 , 1952, pp. 812–830 (English, rruff.info [PDF; 1,2 MB ; accessed on October 20, 2019]).
  8. ↑ Laumontite. In: mindat.org. Hudson Institute of Mineralogy, accessed October 20, 2019 .
  9. ↑ Héricart de Thury: Francois Pierre Nicolas Gillet de Laumont (1747-1834) . In: Annales des Mines . 1834, p. 523– (French, annales.org [accessed September 8, 2019]).
  10. ↑ Hans Lüschen: The names of the stones. The mineral kingdom in the mirror of language . 2nd Edition. Ott Verlag, Thun 1979, ISBN 3-7225-6265-1 , p. 263 .
  11. ^ Robert Jameson: System of Mineralogy. tape II . Bell and Bradfute, Edinburgh, UK 1805, p. 539-540 (English, rruff.info [PDF; 103 kB ; accessed on October 20, 2019]).
  12. ↑ René-Just Haüy : Tableau Comparatif des Résultats de Cristallographie et de l'Analyse Chimique Relativement à la Classification des Minéraux . Courcier, Paris 1809, p.  195–196 (French, rruff.info [PDF; 103 kB ; accessed on October 20, 2019]).
  13. ^ Karl Caesar von Leonhard : Handbuch der Oryktognosie . Mohr and Winter, Heidelberg 1821, p.  448–449 ( rruff.info [PDF; 137 kB ; accessed on October 20, 2019]).
  14. ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
  15. ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed October 20, 2019 .
  16. ^ EP Henderson and Jewell J. Glass: Additional notes on laumontite and thomsonite from Table Mountain, Colorado . In: American Mineralogist . tape 18 , 1933, pp. 402–406 (English, minsocam.org [PDF; 288 kB ; accessed on October 12, 2019]).
  17. ↑ a b Atsushi Yamazaki, Takahiro Shiraki, Hirotsugo Nishido and Ryohei Otsuka: Phase Change of Laumonite Under Relative Humidity — Controlled Conditions . In: Clay Science . tape 8 , 1991, pp. 79–86 (English, jstage.jst.go.jp [PDF; 555 kB ; accessed on October 20, 2019]).
  18. ↑ a b c Thráinn Fridriksson, David L. Bish, Dennis K. Bird: Hydrogen-bonded water in laumontite I: X-ray powder diffraction study of water siteoccupancy and structural changes in laumontite during room-temperature isothermalhydration / dehydration . In: American Mineralogist . tape 88 , 2003, p. 277–287 (English, rruff.info [PDF; 558 kB ; accessed on October 20, 2019]).
  19. ↑ a b Irina Kiseleva, Alexandra Navrotsky, Igor A. Belitsky, Boris A. Fursenko: Thermochemistry of natural potassium sodium calcium leonhardite and its cation-exchanged forms . In: American Mineralogist . tape 81 , 1996, pp. 668–675 (English, rruff.info [PDF; 949 kB ; accessed on October 20, 2019]).
  20. ↑ a b Jano Stolz, Thomas Armbruster: X-ray single-crystal structure refinement of Na, K-rich laumontite, originally designated 'primary leonhardite' . In: New yearbook for mineralogy, monthly books . tape 3 , 1997, p. 131-144 , doi : 10.1127 / njmm / 1997/1997/131 (English).
  21. ↑ Ch. Baerlocher and LB McCusker: Building scheme for LAU . In: Structure Commission of the International Zeolite Association IZA-SC (Ed.): Database of Zeolite Structures . (English, iza-structure.org [PDF; 198 kB ; accessed on October 20, 2019]).
  22. ↑ Ch. Baerlocher and LB McCusker: LAU Accessible Volumes and Areas . In: Structure Commission of the International Zeolite Association IZA-SC (Ed.): Database of Zeolite Structures . (English, europe.iza-structure.org [accessed October 20, 2019]).
  23. ↑ Leonhardite. In: mindat.org. Hudson Institute of Mineralogy, accessed October 20, 2019 .
  24. ↑ 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, Ekkehard 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 . In: The Canadian Mineralogist . tape 35 , 1997, pp. 1571–1606 (English, rruff.info [PDF; 3.5 MB ; accessed on October 20, 2019]).
  25. ↑ a b c d e JG Liou, Christian de Capitani, Martin Frey: Zeolite equilibria in the system CaAl 2 Si 2 0 8 - NaAlSi 3 O 8 - SiO 2 - H 2 O . In: New Zealand Journal of Geology and Geophysics . tape 34 , 1991, pp. 293–301 (English, tandfonline.com [PDF; 1.3 MB ; accessed on October 20, 2019]).
  26. ↑ a b Irina Kiseleva, Alexandra Navrotsky, Igor A. Belitsky, Boris A. Fursenko: Thermochemistry and phase equilibria in calcium zeolites . In: American Mineralogist . tape 81 , 1996, pp. 658–667 (English, minsocam.org [PDF; 964 kB ; accessed on October 20, 2019]).
  27. ↑ JG Liou: P-T Stabilities of Laumontite, Wairakite, Lawsonite, and Related Minerals in the system CaAI 2 Si 2 O 8 -SiO 2 -H 2 O . In: Journal of Petrology . tape 12 , 1971, p. 379-411 , doi : 10.1093 / petrology / 12.2.379 (English).
  28. ^ PS Neuhoff, DK Bird: Partial dehydration of laumontite: thermodynamic constraints and petrogenetic implications . In: Mineralogical Magazine . tape 65 , 2001, p. 59-70 , doi : 10.1180 / 002646101550127 (English).
  29. ↑ Localities for Laumontite. In: mindat.org. Hudson Institute of Mineralogy, accessed October 20, 2019 .
  30. ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia (=  Dörfler Natur ). Edition Dörfler im Nebel-Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 275 .
  31. ↑ List of localities for laumontite from the Mineralienatlas and Mindat , accessed on October 20, 2019.