Fluoronatrocoulsellite

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Fluoronatrocoulsellite
General and classification
other names
  • IMA 2009-070
  • Coulsellite
chemical formula
  • (Na 1.5 Ca 0.5 ) (Mg 1.5 Al 0.5 ) F 6 F
  • (Na, Ca) 2 (Mg, Al) 2 F 6 F
  • CaNa 3 AlMg 3 F 14
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		4.DH.15
?
Crystallographic Data
Crystal system trigonal
Crystal class ; symbol ditrigonal-scalenohedral; 3  2 / m
Space group R 3 m (No. 166)Template: room group / 166
Lattice parameters a  = 7.1620  Å ; c  = 17.5972 Å
Formula units Z  = 1
Frequent crystal faces {0001}, {12 3 1}
Twinning no
Physical Properties
Mohs hardness 4.5
Density (g / cm 3 ) 2.99 (measured), 2.994 to 3.001 (calculated)
Cleavage no
Break ; Tenacity clamshell; brittle
colour colorless to white
Line color White
transparency translucent to translucent
shine Glass gloss
Crystal optics
Refractive index n  = 1.40
Optical character isotropic

Fluoronatrocoulsellite is a very rare mineral from the mineral class of oxides and hydroxides . It crystallizes in the trigonal crystal system with the composition (Na 1.5 Ca 0.5 ) (Mg 1.5 Al 0.5 ) F 6 F, so it is a sodium - calcium - magnesiate with X - and Y characterized by fluorine ions -Position.

Fluoronatrocoulsellite was found for the first time in the form of pseudo-octahedral crystals with a maximum size of 2 mm, which show the planar forms {0001} and {12 3 1}. Its type locality is since 1986 silent lying tin - copper - bismuth - mine the "Mt Cleveland Mine" ( coordinates of the deposit Mt Cleveland Mine ), which is 14 km southwest of Waratah in the mining settlement Luina in Heazlewood district, Waratah-Wynyard Municipality , western Tasmania , Australia .

This deposit, Australia's second most important tin supplier since 1968, is also a type locality for Luinait- (OH) (IMA 2009-046), a representative of the tourmaline group with the formula Na (Fe 2+ ) 3 Al 6 (Si 6 O 18 ) (BO 3 ) 3 (OH) 3 (OH).

Etymology and history

In 1986 the Tasmanian mineral collector Peter Hall donated a number of well-crystallized minerals from the “Mt Cleveland Mine” in Tasmania to the Museum of Victoria. Initial investigations showed that there were mainly fluorine-rich species such Morinit , Gearksutite and a calcium-containing Ralstonite -like mineral and potassium-rich feldspar , siderite and Vivianit acted. The well-formed crystals of the Ca-containing ralstonite -like mineral were examined by William Birch and Allan Pring , who published their results in 1990. The chemical composition suggested a new mineral, but difficulties in determining the crystal structure prevented a full description.

The physical, chemical and structural properties of the mineral from the "Mt Cleveland Mine" could later be fully determined. It was submitted to the International Mineralogical Association (IMA), which recognized it in 2009 under the temporary designation IMA 2009-070 . The first scientific description of this mineral was made in 2009 by an Australian research team with William D. Birch, Ian E. Gray , W. Gus Mumme and Allan Pring in the Australian journal of Mineralogy . The authors named the new mineral in honor of Ruth Elise Coulsell (1912-2000) as Coulsellite ( English Coulsellite ). Ruth Coulsell, an "enthusiastic collector, generous benefactor, and committed teacher," was a founding and honorary member of the Mineralogical Society of Victoria.

Although William Birch and Allan Pring recognized the mineral as ralstonite -like and Willian Birch and colleagues recognized the structure of coulsellite as a modified pyrochlore framework in 2009, when the nomenclature of the "pyrochlore group" was revised , coulsellite became the new pyrochlore upper group (pyrochlore -Supergruppe) "forget". It was not until 2017, after recognition by the International Mineralogical Association (IMA) had taken place, that Daniel Atencio , Marcelo B. Andrade , Artur Cezar Bastos Neto and Vitor Paulo Pereira renamed the coulsellite to fluornatrocoulsellite and divided it into the coulsellite group within the Pyrochlore upper group. During the further revision of the nomenclature of the pyrochlore upper group (pyrochlore supergroup) it was also determined that the representative of the pyrochlore upper group with a B position dominated by M 2+ cations in the crystal lattice and below that the dominance of Mg and one by F - Dominated X position are to be placed in the coulsellite group. However, since a mineral group must consist of at least two minerals, the coulsellite group cannot currently (2018) be regarded as a mineral group, as fluoronatrocoulsellite would currently be the only member of this group. Fluoronatrocoulsellite is therefore regarded as a non-assigned representative of the pyrochlore upper group. The name "Coulsellite" has been discredited.

The type material for fluoronatrocoulsellite ( coulsellite ) is stored under catalog number M41450 (holotype) in the collection of the "Museum Victoria" in Melbourne , Australia , which is part of the Melbourne Museum .

classification

The current classification of the International Mineralogical Association (IMA) counts fluoronatrocoulsellite to the pyrochlore upper group with the general formula A 2– m B 2 X 6– w Y 1– n , in which A , B , X and Y have different positions in the structure the minerals of the pyrochlore upper group with A = Na, Ca, Sr, Pb 2+ , Sn 2+ , Sb 3+ , Y, U, □, or H 2 O; B = Ta, Nb, Ti, Sb 5+ or W; X = O, OH or F and Y = OH - , F, O, □, H 2 O or very large (>> 1.0 Å) monovalent cations such as K, Cs or Rb. To pyrochlore supergroup include not only Fluornatrocoulsellit still Fluorcalciomikrolith , Fluornatromikrolith , Hydrokenomikrolith , Hydroxycalciomikrolith , Hydroxykenomikrolith , Kenoplumbomikrolith , Oxynatromikrolith , Oxystannomikrolith , Oxystibiomikrolith , Cesiokenopyrochlor , Fluorcalciopyrochlor , Fluornatropyrochlor , Hydrokenopyrochlor , Hydropyrochlor , Hydroxycalciopyrochlor , Hydroxykenopyrochlor , Hydroxymanganopyrochlor , Hydroxynatropyrochlor , Oxycalciopyrochlor , Fluorcalcioroméit , Hydroxycalcioroméit , Hydroxyferroroméit , Oxycalcioroméit , Oxyplumboroméite , Hydrokenoelsmoreit , Hydroxykenoelsmoreit and Hydrokenoralstonit . Fluoronatrocoulsellite is currently an unassigned representative of the pyrochlore upper group. If another member of the pyrochlore upper group is detected with Mg 2+ dominance on the B position and F - dominance on the X position, the coulsellite group would be established within the pyrochlore upper group .

The 8th edition of the mineral systematics according to Strunz , which is now outdated, but in some cases still in use , lists neither the fluoronatrocoulsellite nor the coulsellite .

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), does not contain either fluoronatrocoulsellite or coulsellite . It would be classified in the department of "oxides with the molar ratio metal: oxygen = 1: 2 and comparable". This is further subdivided according to the relative size of the cations involved and the crystal structure, so that the mineral is classified according to its composition and structure in the subsection “With large (± medium-sized) cations; Layers of edge-linked octahedra ”would be found where, together with all representatives of the pyrochlore, microlith, Betafit, Roméit and Elsmoreit groups, the pyrochlore supergroup with the system no. 4.DH.15 would form. Fluoronatrocoulsellite would be the only representative in the newly created coulsellite group.

Also the systematics of minerals according to Dana , which is mainly used in the English-speaking world , does not yet know the fluorous atomocoulsellite (as well as the coulsellite ).

Chemism

Twelve microprobe analyzes on fluoronatrocoulsellite grains from the "Mt Cleveland Mine" resulted in mean values ​​of 5.93% aluminum; 8.41% calcium; 14.9 magnesium; 14.2% sodium; 54.8% fluorine, 1.81% oxygen, 0.49% phosphorus, total 100.54%. On the basis of 14 anions per formula unit, the empirical formula Ca 0.98 Na 2.88 Al 1.03 Mg 2.86 P 0.07 F 13.47 (OH) 0.53 was calculated from the chemical analysis for fluoronatrocoulsellite , which was simplified to CaNa 3 AlMg 3 F 14 and contents of 5.67% Al; 8.43% Ca; 15.4 Mg; 14.5% Na and 56.0% F (total 100.00%) required. Daniel Atencio and colleagues changed the formula to (Na, Ca) 2 (Mg, Al) 2 F 6 F when the coulsellite was incorporated as fluoronatrocoulsellite in the pyrochlore upper group . The official formula of the IMA is given as (Na 1.5 Ca 0.5 ) (Mg 1.5 Al 0.5 ) F 6 F.

Fluoronatrocoulsellite is the only mineral to date with the element combination Na - Ca - Mg - Al - F. Chemically similar is u. a. Fluorocarmoite (BaNa) , Ba □ Na 2 Na 2 □ CaMg 13 Al (PO 4 ) 11 (PO 3 OH) F 2 .

Within the pyrochlore upper group there are theoretically a multitude of substitution possibilities due to the four different positions to be occupied. Across all subgroups, fluoronatrocoulsellite is the Mg-dominant analogue of Ta 5+ -dominated fluoronatromicrolite and Nb 5+ -dominated fluoronatropyrochloride.

Crystal structure

Fluoronatrocoulsellite crystallizes in the trigonal crystal system in the space group R 3 m (space group no. 166) with the lattice parameters a = 7.1620  Å and c = 17.5972 Å as well as one formula unit per unit cell . The crystal structure of fluoronatrocoulsellite ( coulsellite ) consists of a pyrochlore-like framework of corner-linked octahedra with the composition AlMg 3 F 12 . The Al and Mg ions are arranged in alternating layers in the direction [111] of the rhombohedral cell. The Mg-centered octahedra form layers of the hexagonal tungsten bronze type (HTP) parallel (111), with the calcium ions in the centers of the hexagonal rings in the HTP layers. The Ca atoms have a trigonal-dipyramidal coordination with six longer Ca-F distances to the F atoms of the hexagonal ring and two shorter Ca-F distances to the fluorine atoms above and below the rings. The HTP layers alternate with the layers containing the AlF 6 octahedra and the Na atoms, which have a pyrochlore-like, disrupted cube-like coordination with NaF 8 . If only the metal atoms are considered, the crystal structure of fluoronatrocoulsellite can be described as an F -centered cubic closest packing of (111) layers, which alternately have the compositions AlNa 3 and Mg 3 Ca. Template: room group / 166

Both Ca: Na on the A position and Al: Mg on the B position have a complete 1: 3 order, which is unique in the structure of the minerals within the pyrochlore upper group.

properties

morphology

Fluonatrocoulsellite develops well-developed crystals up to a maximum of 2 mm in size at its type locality, which are mostly fused together to form crust-shaped aggregates . The pseudooctahedral crystals probably represent combinations of the basic pinacoid {0001} and the ditrigonal scalenohedron {12 3 1}. Twinning cannot be visually observed on the crystals, but is demonstrated by the X-ray diffraction diagrams.

physical and chemical properties

The crystals of fluonatrocoulsellite are colorless to white, while their line color is always white. The surfaces of the translucent to transparent fluoronatrocoulsellite show a glass-like sheen , which corresponds very well with the low value for the refraction of light (n = 1.40). Fluonatrocoulsellite is optically isotropic and has no birefringence .

Fluonatrocoulsellite is neither cleavable nor divisible . However, the mineral breaks like quartz , with the fracture surfaces being shell-shaped. With a Mohs hardness of 4.5, the mineral is one of the medium-hard minerals, stands between the reference minerals fluorite (hardness 4) and apatite (hardness 5) and, like these, can be more (hardness 4) or less (hardness 5) easily with a pocket knife scratch. The measured density is 2.99 g / cm³, the data for the calculated density vary between 2.994 g / cm³ and 3.001 g / cm³.

The mineral does not fluoresce in short or long wave UV light . There is no information on chemical behavior.

Education and Locations

Fluoronatrocoulsellite is found at the type locality on quartz - fluorite stages, on which there is a white crust made of unusual, sometimes extraordinarily well-developed minerals such as gearksutite and morinite. Fluoronatrocoulsellite is an early formation in this sequence of fluorine-rich minerals and often sits directly on the quartz. Morinite and Gearksutite follow in the succession, suggesting a crystallization from Na-Ca-Mg-containing solutions, which suggests from reactions between fluorine-containing magmatic brines and the surrounding carbonatic rocks. The fluorine-rich minerals probably represent a low-temperature association, as it is characteristic of mineralized dikes of a late formation stage and drusen. The exact location of the fluorine-rich stairs and you find time are unknown, but they are in the 1970s in fault zones hiss of the 11th and the 15th floor have been found. At Vesuvius, fluoronatrocoulsellite is a volcanogenically formed sublimate in volcanic slags generated during the 1944 eruption . In the "Katuginskoe" deposit, the mineral is found in alkali-rich granites such as B. biotite - amphibole - granites in which annite was displaced by riebeckite and microcline by albite , which is explained by the effects of moderately alkaline Na-F solutions with low Ca concentration on the biotite granite.

Typical accompanying minerals of Fluonatrocoulsellits in its type material are Gearksutite, Morinit, orthoclase ( Adular ) Bertrandit , siderite, pyrite and Vivianit in a matrix of quartz and fluorite. At the time locality, the Vesuvius, Fluonatrocoulsellit is in a lead-rich socialization of Parascandolait , Opal , Cerussite , Mimetite and phoenicochroite accompanied while its mineral assemblage at the third location, the REE - niobium - tantalum -Lagerstätte of Katugin complex from Neighborit , Gagarinit , Fluocerit and Tveitite- (Y) consists.

As a very rare mineral formation, fluonatrocoulsellite could only be described from four sites so far (as of 2018). The type locality for Fluonatrocoulsellit is 14 km southwest of Waratah in the mining settlement Luina in Heazlewood district, Waratah-Wynyard Municipality , western Tasmania , Australia , located Tin - Copper - bismuth - deposit of "Mt Cleveland Mine".

The Cleveland deposits were explored in 1962–1964, and a detailed investigation with underground exploration, detailed sampling and metallurgical testing was carried out in 1964–1966. The "Mt Cleveland Mine" has been an important solid rock deposit since the start of production in February 1968, delivering approximately 5.5 megatons of ore by June 1884, from which 24,000 tons of tin and 9,592 tons of copper have been recovered. The deposit was wiped out in 1986 and was discarded at that time. The most important part of the deposit with numerous veins contained lenses with pyrrhotite , pyrite , marcasite and cassiterite as well as accessory sulphides , silicates and fluorite in a gangue of mainly quartz and carbonates.

Further locations for fluoronatrocoulsellite are:

There are no known sites for fluoronatrocoulsellite in Germany , Austria and Switzerland .

use

Due to its rarity, fluoronatrocoulsellite is of no practical importance and is only of interest to mineral collectors.

See also

literature

  • William D. Birch, Allan Pring: A calcian ralstonite-like Mineral from the Cleveland Mine, Tasmania, Australia . In: Mineralogical Magazine . tape 54 , no. 377 , 1990, pp. 559–602 , doi : 10.1180 / minmag.1990.054.377.11 (English, rruff.info [PDF; 740 kB ; accessed on December 4, 2018]).
  • William D. Birch, Ian E. Gray, W. Gus Mumme, Allan Pring: Coulsellite, a new mineral from the Cleveland mine, Luina, Tasmania . In: Australian Journal of Mineralogy . tape 15 , 2009, p. 21-24 (English).
  • Daniel Atencio, Marcelo B. Andrade, Artur Cezar Bastos Neto, Vitor Paulo Pereira: Ralstonite Renamed Hydrokenoralstonite, Coulsellite Renamed Fluornatrocoulsellite, and Their Incorporation Into the Pyrochlore Supergroup . In: The Canadian Mineralogist . tape 55 , no. 1 , 2017, p. 115–120 , doi : 10.3749 / canmin.1600056 (English, researchgate.net [PDF; 629 kB ; accessed on November 26, 2018]).

Web links

Individual evidence

  1. ↑ a b c d e f Daniel Atencio, Marcelo B. Andrade, Artur Cezar Bastos Neto, Vitor Paulo Pereira: Ralstonite Renamed Hydrokenoralstonite, Coulsellite Renamed Fluornatrocoulsellite, and Their Incorporation Into the Pyrochlore Supergroup . In: The Canadian Mineralogist . tape 55 , no. 1 , 2017, p. 115–120 , doi : 10.3749 / canmin.1600056 (English, researchgate.net [PDF; 629 kB ; accessed on November 26, 2018]).
  2. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai William D. Birch, Ian E. Gray, W. Gus Mumme , Allan Pring: Coulsellite, a new mineral from the Cleveland mine, Luina, Tasmania . In: Australian Journal of Mineralogy . tape 15 , 2009, p. 21-24 (English).
  3. ↑ a b c d e W. Gus Mumme, Ian E. Gray, William D. Birch, Allan Pring, Catherine Bougerol, Nicholas C. Wilson: Coulsellite, CaNa 3 AlMg 3 F 14 , a rhombohedral pyrochlore with 1: 3 ordering in both A and B sites, from the Cleveland mine, Tasmania, Australia . In: The American Mineralogist . tape 95 , no. 5-6 , 2010, pp. 736-740 , doi : 10.2138 / am.2010.3360 (English).
  4. ^ A b c d e William D. Birch, Allan Pring: A calcian ralstonite-like Mineral from the Cleveland Mine, Tasmania, Australia . In: Mineralogical Magazine . tape 54 , no. 377 , 1990, pp. 559–602 , doi : 10.1180 / minmag.1990.054.377.11 (English, rruff.info [PDF; 740 kB ; accessed on December 4, 2018]).
  5. ^ Donald David Hogarth: Classification and nomenclature of the pyrochlore group . In: The American Mineralogist . tape 62 , 1977, pp. 403-410 (English, rruff.info [PDF; 849 kB ; accessed on September 3, 2018]).
  6. ^ A b Daniel Atencio, Marcelo B. Andrade, Andrew G. Christy, Reto Gieré, Pavel M. Kartashov: The Pyrochlore supergroup of minerals: Nomenclature . In: The Canadian Mineralogist . tape 48 , 2010, p. 673–698 , doi : 10.3749 / canmin.48.3.673 (English, rruff.info [PDF; 1,4 MB ; accessed on August 30, 2018]).
  7. ^ Andrew G. Christy, Daniel Atencio: Clarification of the status of species in the pyrochlore supergroup . In: Mineralogical Magazine . tape 77 , no. 1 , 2013, p. 13–20 , doi : 10.1180 / minmag.2013.077.1.02 (English, cnmnc.main.jp [PDF; 85 kB ; accessed on August 30, 2018]).
  8. ↑ Ulf Hålenius, Frédéric Hatert, Marco Pasero, Stuart J. Mills: IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) NEWSLETTER 32: New minerals and nomenclature modifications approved in 2016 . In: Mineralogical Magazine . tape 80 , no. 5 , 2016, p. 915–922 , doi : 10.1180 / minmag.2016.080.084 (English).
  9. ↑ Stuart J. Mills, Frédéric Hatert, Ernest H. Nickel, Giovanni Ferraris: The standardization of mineral group hierarchies: application to recent nomenclature proposals . In: European Journal of Mineralogy . tape 21 , 2009, p. 1073-1080 , doi : 10.1127 / 0935-1221 / 2009 / 0021-1994 (English, researchgate.net [PDF; 532 kB ; accessed on December 1, 2018]).
  10. ↑ a b Fluoronatrocoulsellite. In: mindat.org. Hudson Institute of Mineralogy, accessed May 2, 2020 .
  11. ↑ Thomas Witzke , Manfred Steins, Thomas Doering, Walter Schuckmann, Reinhard Wegner, Herbert Pöllmann: Fluornatromicrolite, (Na, Ca, Bi) 2 Ta 2 O 6 F, a new mineral species from Quixaba, Paraíba, Brazil . In: The Canadian Mineralogist . tape  49 , 2011, p. 1105–1110 , doi : 10.3749 / canmin.49.4.1105 (English, rruff.info [PDF; 849 kB ; accessed on September 3, 2018]).
  12. ↑ Yin Jingwu, Li Guowu, Yang Guangming, Ge Xiangkun, Xu Haiming, Wang Jun: Fluornatropyrochlore, a new pyrochlore supergroup mineral from the Boziguoer rare earth element deposit, Baicheng County, Akesu, Xinjiang, China . In: The Canadian Mineralogist . tape 53 , 2015, p. 455–460 , doi : 10.3749 / canmin.1500007 (English, cugb.edu.cn [PDF; 1.6 MB ; accessed on September 24, 2018]).
  13. ↑ a b c Francesco Demartin, Italo Campostrini, Carlo Castellano, Massimo Russo: Parascandolaite, KMgF 3 , a new perovskite-type fluoride from Vesuvius . In: Physics and Chemistry of Minerals . tape 41 , 2014, p. 403–407 , doi : 10.1007 / s00269-014-0668-y (English, researchgate.net [PDF; 826 kB ; accessed on December 4, 2018]).
  14. ↑ a b c Valentina B. Savel'eva, Ekaterina P. Bazarova, Elena A. Khromova, SV Kanakin: Fluorides and Fluorcarbonates in Rocks of the Katugin Complex, Eastern Siberia: Indicators of Geochemical Mineral Formation Conditions . In: Geology of Ore Deposits . tape 59 , no. 7 , 2017, p. 561-574 , doi : 10.1134 / S1075701517070108 (English).
  15. ↑ Fluoronatrocoulsellite. In: mindat.org. Hudson Institute of Mineralogy, accessed May 2, 2020 .
  16. ↑ Find location list for Fluornatrocoulsellite at the Mineralienatlas and at Mindat (accessed on December 4, 2018)
  17. ^ Roy Cox, Edward V. Dronseika: The Cleveland Stratabound Tin Deposits, Tasmania, Australia: A Review of Their Economic Geology, Exploration, Evaluation and Production . In: Charles S. Hutchison (Ed.): Geology of Tin Deposits in Asia and the Pacific (=  Mineral Concentrations and Hydrocarbon Accumulations in the ESCAP Region . Volume 3 ). 1st edition. Springer, Berlin 1988, ISBN 3-540-17954-2 , pp. 112-123 (English).