Hydroxynatropyrochlore

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Hydroxynatropyrochlore
General and classification
other names

IMA 2017-074

chemical formula (Na, Сa, Ce) 2 Nb 2 O 6 (OH)
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		4.DH.15 ( 8th edition : IV / C.17)
02/08/01. ??
Crystallographic Data
Crystal system cubic
Crystal class ; symbol cubic hexakisoctahedral; 4 / m  3  2 / m
Space group Fd 3 m (No. 227)Template: room group / 227
Lattice parameters a  = 10.3276  Å
Formula units Z  = 8
Frequent crystal faces {100}, {111}
Twinning no
Physical Properties
Mohs hardness ≈ 5
Density (g / cm 3 ) 4.60 (measured); 4.77 (calculated)
Cleavage clearly after (111)
Break ; Tenacity clamshell; brittle
colour pale brown; light brown in transmitted light
Line color White
transparency translucent to translucent
shine Diamond to greasy gloss
Crystal optics
Refractive index n  = 2.10
Optical character isotropic
Other properties
Chemical behavior slowly soluble in hot HCl
Special features no fluorescence

Hydroxynatropyrochlore is a very rare mineral from the mineral class of oxides and hydroxides . It crystallizes in the cubic crystal system with the composition (Na, Сa, Ce) 2 Nb 2 O 6 (OH), so it is a sodium - calcium - cerium - niobate with additional hydroxide ions.

Hydroxynatropyrochlore occurs at its type locality in the phosphorite and calcite - carbonatite in the form of cubic and cuboctahedral crystals of maximum 0.7 mm in size, which contain relics of amorphous uranium- rich hydroxykenopyrochlore. In the vein- shaped dolomite carbonatites it also forms idiomorphic cuboctahedral crystals up to 0.3 mm in size with thin, up to 50 μm thick marginal zones of U-rich hydroxykenopyrochlore.

The type locality of Hydroxynatropyrochlors is a Phoscorit Carbonatite in the solid mass of kovdor ( coordinates of the kovdor massif ) in the Murmansk oblast , Federal District Northwestern Russia , Russia .

Etymology and history

In the Kowdor chimney , minerals of the pyrochlore upper group are relatively widespread. As early as 2002, Gregory Ivanyuk and colleagues established that around a quarter of these minerals in Kowdor consist of a Na-Nb-OH-dominated phase. This Na-Nb-OH-dominated phase was already known in other alkali rock and alkali rock ultrabasite massifs such as the Chibinen or Sebl'javr. However, it has never been fully characterized, in particular the determination of the fluorine content, crystal structure data etc. was missing . Only with the discovery of further occurrences of this phase in the ores of Kowdor was a complete description of the new mineral, especially with the data from the various occurrences in Kowdor possible. The new mineral was presented to the International Mineralogical Association (IMA), which recognized it in 2017 under the provisional designation "IMA 2017-074". The first scientific description of this mineral was made in 2018 by a Russian research team with Gregory Yu. Ivanyuk , Victor N. Yakovenchuk , Taras L. Panikorovskii , Nataliya Konoplyova , Yakov A. Pakhomovsky , Ayya ​​V. Bazai , Vladimir N. Bocharov and Sergey V. Krivovichev in the English science magazine Mineralogical Magazine . The authors named the new mineral in accordance with the nomenclature of the pyrochlore upper group due to its chemical composition with an A position dominated by sodium , a B position dominated by niobium and a Y position dominated by hydroxy groups as hydroxynatropyrochlore ( English: hydroxynatropyrochlore ).

The type material for Hydroxynatropyrochlore is stored under catalog number 1/19679 (holotype) in the collection of the Mineralogical Museum of the State University of Saint Petersburg in Saint Petersburg , Russia.

Pyrochlore was originally found by Nils Otto Tank (1800–1864) near Stavern in the Norwegian province of Vestfold and described in 1826 by Friedrich Wöhler . Wöhler named the mineral based on a suggestion by Jöns Jakob Berzelius after the Greek words πῦς [ pyr ] and χλωρός [ chlorós ] for "fire" and "green" because of its property, after melting with phosphorus salt (sodium ammonium hydrogen phosphate) before Solder tube to solidify to a grass-green glass. Over the decades, the term pyrochlore has often been used unspecifically and often without the background of chemical analysis. The mineral pyrochlore was discredited in 2010.

classification

The current classification of the International Mineralogical Association (IMA) counts the hydroxynatropyrochlore 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 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 Hydroxynatropyrochlor still Fluorcalciomikrolith , Fluornatromikrolith , Hydrokenomikrolith , Hydroxycalciomikrolith , Hydroxykenomikrolith , Kenoplumbomikrolith , Oxynatromikrolith , Oxystannomikrolith , Oxystibiomikrolith , Cesiokenopyrochlor , Fluorcalciopyrochlor , Fluornatropyrochlor , Hydrokenopyrochlor , Hydropyrochlor , Hydroxycalciopyrochlor , Hydroxykenopyrochlor , Hydroxymanganopyrochlor , Oxycalciopyrochlor , Fluorcalcioroméit , Hydroxycalcioroméit , Hydroxyferroroméit , Oxycalcioroméit , Oxyplumboroméite , Hydrokenoelsmoreit , Hydroxykenoelsmoreit , Fluornatrocoulsellit and Hydrokenoralstonit . Hydroxynatropyrochlor, together with cesiokenopyrochlor, fluorcalciopyrochlor, fluoronatropyrochlore, hydrokenopyrochlor, hydropyrochlore, hydroxycalciopyrochlor, hydroxykenopyrochlor, hydroxymanganopyrochlor and oxycalciopyrochlor within the pyrochlore upper group, forms the pyrochlore group .

The 8th edition of the mineral classification according to Strunz , which is now outdated, but still in use in some cases, does not yet list hydroxynatropyrochlore. It would belong to the mineral class of "oxides and hydroxides" and there to the general division of "oxides with a metal: oxygen ratio = 2: 3 (M 2 O 3 and related compounds)", where together with bariopyrochlore (discredited 2010, possibly " Zero-valent-dominant pyrochlore "), bismuthopyrochlore (discredited 2010, possibly" Oxynatropyrochlore "), Calciobetafit (discredited 2010), Ceriopyrochlor- (Ce) (discredited 2010, possibly" Fluorkenopyrochlore "), Kalipyrochlore (2010 redefined to hydropyrochlore), Plumbopyrochlor (discredited 2010, possibly "Oxyplumbopyrochlor" or "Kenoplumbopyrochlor"), Pyrochlore (discredited 2010, since then group and parent group name; this includes the possibly new species "Oxynatropyrochlor", "Hydroxycalciopyrochlor", "Fluorcalciopyrochlor" and "Fluorkenopyrochlor"), Uranpyrochlor (discredited 2010, possibly “Oxynatropyrochlor”), Strontiopyrochlor (discredited 2010, possibly “Fluorstrontiopyroc hlor "or" Fluorkenopyrochlor ") and Yttropyrochlor- (Y) (discredited 2010, possibly" Oxyyttropyrochlor- (Y) ") the" Pyrochlore Group, Pyrochlore Subgroup "with the system no. IV / C.17 would have 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), also does not yet recognize hydroxynatropyrochlore. 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. Hydroxynatropyrochlor would be doing with Fluorcalciopyrochlor , Fluornatropyrochlor , Fluorkenopyrochlor , Fluorstrontiopyrochlor , Hydropyrochlor (formerly Kalipyrochlor ) Hydroxycalciopyrochlor , Kenoplumbopyrochlor , Oxycalciopyrochlor (formerly Stibiobetafit ) Oxynatropyrochlor , Oxyplumbopyrochlor and Oxyyttropyrochlor- (Y) found in the Pyrochlorgruppe.

Also the systematics of minerals according to Dana , which is mainly used in the English-speaking area , does not yet know the hydroxynatropyrochlore. It would be classified in the class of "oxides and hydroxides", but there in the department of "multiple oxides with Nb, Ta and Ti". Here he was, along with pyrochlore , Kalipyrochlor , Bariopyrochlor , Yttropyrochlor- (Y) , Ceriopyrochlor- (Ce) , Plumbopyrochlor , Uranpyrochlor , Strontiopyrochlor and Bismutopyrochlor (all since 2010 discredited. See under classification of minerals by Strunz 8th edition) the "pyrochlore subgroup; Nb> Ta; (Nb + Ta)> 2 (Ti) “with the system no. 08.02.01 to be found within the subsection of " Multiple oxides with Nb, Ta and Ti with the formula A 2 (B 2 O 6 ) (O, OH, F) ".

Chemism

Microprobe analyzes on two different hydroxynatropyrochlore grains from the type locality yielded mean values ​​of 7.97% Na 2 O; 10.38% CaO; 4.71% TiO 2 ; 0.42% FeO; 56.44% Nb 2 O 5 ; 3.56% Ce 2 O 3 ; 4.73% Ta 2 O 5 ; 5.73% ThO 2 ; 3.66% UO 2 ; 0.05% F; 2.37% H 2 O (estimated from the mass deficit; presence of OH confirmed by Raman spectroscopy ) and [(O ≡ F) –0.02%, sum = 100.00%]. On the basis of Nb + Ta + Ti = 2 atoms per formula unit, the empirical formula (Na 1.02 Ca 0.73 Ce 0.09 Th 0.09 U 0.05 Fe 2+ 0.02 ) Σ = 2 , 00 (Nb 1.68 Ti 0.23 Ta 0.09 ) Σ = 2.00 O 6.03 (OH 1.04 F 0.01 ) Σ = 1.05 , which corresponds to (Na, Ca, Ce ) 2 Nb 2 O 6 (OH) has been simplified.

The only mineral besides hydroxynatropyrochlore with the element combination Na - Nb - O - H is Franconite , Na (Nb 2 O 5 ) (OH) · 3H 2 O. Chemically similar is u. a. Fersmit , (Ca, Ce, Na) (Nb, Ta, Ti) 2 (O, OH, F) 6 .

In the minerals of the pyrochlore upper group of the phosphorite-carbonatite complex of Kovdor, both the sodium and calcium contents decrease in the A position to the same extent as the sum of the contents of elements with high charges (REE + Th + U) increases. This indicates that natropyrochlore is a result of the complex substitution of Ca 2+ by REE 3+ , Th 4+ and U 4+ (± Na + and □) in the Na-Ca-pyrochlore mixed crystal series, (NaCa) Nb 2 O 6 (OH, F), according to NaCa ↔ NaCa 0.7 REE 0.2 □ 0.1 ; NaCa ↔ NaCa 0.5 (Th, U) 0.25 □ 0.25 ; NaCa ↔ Na 1.5 REE 0.5 ; NaCa ↔ Na 1.6 (Th, U) 0.1 □ 0.3 etc. is. If the sum (U + Th) assumes contents of> 20% by weight, this leads to a metamictization of the mineral, a decrease in Na and Ca, an increase in the H 2 O content and finally to the transformation of the mineral into hydroxykenopyrochlore. The F content of natropyrochlore varies between 0 and 0.51 apfu (atoms per formula unit), so that a small part of the samples examined corresponds to the mineral fluoronatropyrochlore.

Within the pyrochlore upper group there are theoretically a multitude of substitution possibilities due to the four different positions to be occupied. Hydroxynatropyrochlore is the OH-dominant analogue of the F-dominated fluoronatropyrochlore and the Na-dominant analogue of the Ca-dominated hydroxycalciopyrochlore, the Mn-dominated hydroxymanganopyrochlore and the vacancy-dominated hydroxykenopyrochlore. Across subgroups, there are no representatives of the pyrochlore upper group with Na dominance on the A position and simultaneous OH dominance on the Y position.

Crystal structure

Hydroxynatropyrochlore crystallizes in the cubic crystal system in the space group Fd 3 m (space group no. 227) with the lattice parameter a = 10.3276  Å and eight formula units per unit cell . Template: room group / 227

The crystal structure of the Hydroxynatropyrochlors can be used as three-dimensional octahedral framework of corner-sharing B O 6 - octahedra are described, wherein in the interstices of this scaffold, the A cations (Na, Ca, Ce, Th, U, Fe 2+ ) and the OH groups sit . The cations Na and Nb occupy positions 16 c and 16 d , respectively , while O and OH are in positions 48 f and 8 a .

The crystal chemical formula of the holotype hydroxynatropyrochloride can be expressed as (Na 1.02 Ca 0.70 □ 0.08 Ce 0.07 Th 0.07 U 0.06 ) Σ = 2.00 (Nb 1.68 Ti 0.19 Ta 0.13 ) Σ = 2.00 [O 5.96 (OH) 0.04 ] Σ = 6.00 (OH) 1.00 can be written, which works well with the above. empirical formula matches.

Hydroxynatropyrochlore is isotypic (isostructural) to all other representatives of the pyrochlore upper group that crystallize in space group Fd 3 m (space group no. 227) . Template: room group / 227

properties

morphology

Hydroxynatropyrochlore is found by its type locality in the phosphorites and calcite carbonatites in the form of well-formed cubic and cuboctahedral crystals of a maximum of 0.7 mm in size, which usually contain irregularly formed relics of amorphous, U-rich hydroxykenopyrochlore. In the dolomite-carbonatite dykes, however, the hydroxynatropyrochlore is observed in idiomorphic cuboctahedral crystals with a maximum size of 0.3 mm, which mostly have a rim zone of U-rich hydroxykenopyrochlore up to 50 μm thick.

physical and chemical properties

The crystals of Hydroxynatropyrochlors are pale brown at the type locality and light brown in transmitted light, while their line color is always white. The surfaces of the translucent to transparent Hydroxynatropyrochlors show a diamond to greasy luster , which corresponds very well with the very high value for the light refraction (n = 2.10). Hydroxynatropyrochlore is optically isotropic.

Hydroxynatropyrochlore is not divisible, but is clearly cleavable according to the {111} octahedron. Due to its brittleness , however , it breaks in a similar way to quartz , with the fracture surfaces being shell-shaped. With a Mohs hardness of ≈ 5, the mineral is one of the medium-hard minerals and, like the reference mineral apatite , can still be scratched with a pocket knife. The measured density for hydroxynatropyrochlore is 4.60 g / cm³, the calculated density is 4.77 g / cm³. Hydroxynatropyrochlor is neither in the long wavelength even in the short wavelength UV light , a fluorescent . There is no information on cathodoluminescence under the electron beam for the mineral.

Hydroxynatropyrochlore is slowly soluble in hot hydrochloric acid (HCl).

Education and Locations

The type locality for hydroxynatropyrochlore is the Kovdor massif in Murmansk Oblast , Northwestern Federal District , Russia . It occurs here as a characteristic accessory mineral both in a phoscorite with only low carbonate content in the contact zone of the phoscorite-carbonatite chimney with the adjacent rock (foidolite) and also in the carbonate-rich phoscorite and the carbonatite from the center of the chimney. “ Phoscorite ” (foscorite) is derived from the name of the “Phosphate Development Corporation” (FOSKOR) in South Africa and describes ultramafic plutonic magnetite - apatite rocks with forsterite , diopside or phlogopite , which occur in close association with carbonatites. The most common secondary components are calcite , dolomite , phlogopite, tetraferriphlogopite and Richterite , the most important accessories are baddeleyite , pyrochlore , pyrrhotite and chalcopyrite . Only about 25 locations for this rock are known worldwide.

Typical Begleitminerale of Hydroxynatropyrochlors on its type locality are calcite, dolomite, forsterite, hydroxyapatite, magnetite and phlogopite, accessory companions are Baddeleyit, barite , Barytocalcit , chalcopyrite, Chamosite - Clinochlore , galena , Gladiusit , Juonniit , ilmenite , magnesite , pyrite , pyrrhotite, quintinite , spinel , Strontianit , Valleriit and Zirkonolith .

In the Kowdor phoscorite-carbonatite chimney, an intensive hydrothermal alteration of primary minerals took place, which was accompanied by the formation of numerous secondary phases such as clinochlor or glagolevite after phlogopite, clinohumite and serpentine after forsterite, pyrochlore and zirconolite after baddeleyite, etc.

The higher content of Nb and Sc in baddeleyite from the central areas of the carbonate-rich phosphorite and carbonatite due to the substitution 2Zr 4+ ↔ Sc 3+ + Nb 5+ led to an intensive displacement of this mineral by representatives of the pyrochlore upper group and the formation of scandium -Phosphates according to

24 baddeleyite (Sc-Nb end link) + 12 dolomite + 8 apatite + 56 H 2 O + 10 CO 2 + 6 Na + → 6 pyrochlore (NaCaNb 2 O 6 (OH)) + 34 calcite + 12 juonniite + 3H 2 .

As a result, the minerals from the pyrochlore upper group occurring in the Kowdor complex are secondary, hydrothermally formed minerals, which were mainly formed during the alteration of niobium-rich baddeleyite. Hydroxynatropyrochlore is formed from a hypothetical Na-Ca-pyrochlore, NaCaNb 2 O 6 (OH), as a result of the preferred substitution of Ca by REE, Th and U. The increase in the content of U and Th leads to a metamictization of the pyrochloride . Furthermore, in the last stage of the formation of the phosphorite-carbonatite chimney, hydroxynatropyrochlore is partially converted into fluoronatropyrochlore with the same contents of OH and F, this reaction being accompanied by a similar conversion of hydroxylapatite to fluoroapatite .

As an extremely rare mineral formation, hydroxynatropyrochlore could only be described worldwide by its type locality (as of 2018). Sites for Hydroxynatropyrochlore in Germany , Austria and Switzerland are therefore unknown.

use

Hydroxynatropyrochlor is due to its Nb 2 O 5 -contents of about 56 wt .-% a rich niobium - ore . The representatives of the pyrochlore upper group are relatively frequent in the phosphorite-carbonatite chimney of Kowdor and, according to EM Epstein and colleagues, achieve economically usable concentrations in the central areas of the chimney.

See also

literature

  • Gregory Yu. Ivanyuk, Victor N. Yakovenchuk, Taras L. Panikorovskii, Nataliya Konoplyova, Yakov A. Pakhomovsky, Ayya V. Bazai, Vladimir N. Bocharov, Sergey V. Krivovichev: Hydroxynatropyrochlore, (Na, С a, Ce) 2 Nb 2 O 6 (OH), a new member of the pyrochlore group from the Kovdor phoscorite-carbonatite pipe (Kola Peninsula, Russia) . In: Mineralogical Magazine . February 2019, doi : 10.1180 / minmag.2017.081.102 (English, accepted article for Mineralogical Magazine, not printed yet).

Web links

Individual evidence

  1. ↑ 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 aj ak al Gregory Yu. Ivanyuk, Victor N. Yakovenchuk, Taras L. Panikorovskii, Nataliya Konoplyova, Yakov A. Pakhomovsky, Ayya V. Bazai, Vladimir N. Bocharov, Sergey V. Krivovichev: Hydroxynatropyrochlore, (Na, С a, Ce) 2 Nb 2 O 6 (OH), a new member of the pyrochlore group from the Kovdor phoscorite-carbonatite pipe (Kola Peninsula, Russia) . In: Mineralogical Magazine . February 2019, doi : 10.1180 / minmag.2017.081.102 (English, accepted article for Mineralogical Magazine, not printed yet).
  2. ↑ a b 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, edu.cn [PDF; 1.6 MB ; accessed on September 24, 2018]).
  3. ↑ a b c d Gregory Yu. Ivanyuk, Victor N. Yakovenchuk, Yakov A. Pakhomovsky: Kovdor . Ed .: Frances Wall. 1st edition. Laplandia Minerals, Apatity 2002, ISBN 5-900395-41-3 , pp. 1–326 (English, Russian).
  4. ↑ Victor N. Yakovenchuk, Gregory Yu. Ivanyuk, Yakov A. Pakhomovsky, Yury P. Men'shikov: Khibiny . Ed .: Frances Wall. 1st edition. Laplandia Minerals, Apatity 2005, ISBN 5-900395-48-0 , pp. 1-468 (English).
  5. ^ VV Subbotin, GF Subbotina: Minerals of the pyrochlore group in phoscorites and carbonatites of the Kola Peninsula . In: Vestnik Murmansk State Technical University . tape 3 , no. 2 , 2000, pp. 273-284 (Russian).
  6. ↑ a b Friedrich Wöhler: About the pyrochlore, a new mineral species . In: Poggendorff's annals of physics and chemistry . tape 7 , no. 4 , 1826, pp. 417-428 ( limited preview in Google Book search).
  7. ^ A b c 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]).
  8. ^ A b 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, main.jp [PDF; 85 kB ; accessed on August 30, 2018]).
  9. ↑ a b Mindat - Hydroxynatropyrochlore , (accessed October 10, 2018) (English)
  10. ↑ Yang Guangming, Li Guowu, Xiong Ming, Pan Baoming, Yan Chenjie: Hydroxycalciopyrochlore, a new mineral species from Sichuan, China . In: Acta Geologica Sinica (english edition) . tape 88 , no. 3 , 2014, p. 748-753 , doi : 10.1111 / 1755-6724.12235 (English).
  11. ↑ Nikita V. Chukanov, Günter Blass, Natalia V. Zubkova, Igor V. Pekov, Dmitry Yu. Pushcharovskii, Heribert Prinz: Hydroxymanganopyrochlore: A New Mineral from the Eifel Volcanic Region, Germany . In: Doklady Earth Sciences . tape 449 , no. 1 , 2013, p. 342-345 , doi : 10.1134 / S1028334X13030100 (English).
  12. ↑ Ritsuro Miyawaki, Koichi Momma, Satoshi Matsubara, Takashi Sano, Masako Shigeoka, Hiroyuki Horiuchi: Hydroxykenopyrochlore, IMA 2017-030a. CNMNC Newsletter No. 39, October 2017, page 1285 . In: Mineralogical Magazine . tape 81 , 2017, p. 1279-1286 (English).
  13. ↑ a b Nataly I. Krasnova, Tomas G. Petrov, Elena G. Balaganskaya, Daniel Garcia, Jacques Moutte, Anatoly N. Zaitsev, Frances Wall: Introduction to phoscorites: occurrence, composition, nomenclature and petrogenesis . In: A. Zaitsev and F. Wall (Eds.): Phoscorites and Carbonatites from Mantle to Mine: the Key Example of the Kola Alkaline Province . Mineralogical Society Series. 1st edition. tape 10 . The Mineralogical Society of Great Britain & Ireland, London 2004, ISBN 0-903056-49-6 , pp. 43–72 , doi : 10.1180 / MSS.10.02 (English, researchgate.net [PDF; accessed October 10, 2018]).
  14. ↑ a b Julia A. Mikhailova, Andrey O. Kalashnikov, Victor A. Sokharev, Yakov A. Pakhomovsky, Nataly G. Konopleva, Victor N. Yakovenchuk, Ayya V. Bazai, Pavel M. Goryainov, Gregory Yu. Ivanyuk: 3D mineralogical mapping of the Kovdor phoscorite – carbonatite complex (Russia) . In: Mineralium Deposita . tape 51 , no. 1 , 2016, p. 131–140 , doi : 10.1007 / s00126-015-0594-z (English).
  15. ↑ a b c Gregory Yu. Ivanyuk, Andrey O. Kalashnikov, Yakov A. Pakhomovsky, JA Mikhailova, Victor N. Yakovenchuk, Nataliya G. Konoplyova, VA Sokharev, Ayya V. Bazai, Pavel M. Goryainov: Economic minerals of the Kovdor baddeleyite-apatite-magnetite deposit, Russia: mineralogy, spatial distribution, and ore processing optimization . In: Ore Geology Reviews . tape 77 , September 2016, p. 279–311 , doi : 10.1016 / j.oregeorev.2016.02.008 (English, researchgate.net [PDF; 6.2 MB ; accessed on October 10, 2018]).
  16. ↑ Mindat - Number of locations for Hydroxynatropyrochlore , (accessed on October 10, 2018) (English)
  17. ↑ List of locations for hydroxynatropyrochlore in the Mineralienatlas and Mindat (accessed on October 10, 2018)
  18. ↑ Andrey O. Kalashnikov, Victor N. Yakovenchuk, Yakov A. Pakhomovsky, Ayya V. Bazai, Victor A. Sokharev, Nataly G. Konopleva, Julia A. Mikhailova, Pavel M. Goryainov, Gregory Yu. Ivanyuk: Scandium of the Kovdor magnetite-apatite-baddeleyite deposit (Murmansk Region, Russia): Mineralogy, spatial distribution, and potential resource . In: Ore Geology Reviews . tape 72 , no. 1 , 2016, p. 532–537 , doi : 10.1016 / j.oregeorev.2015.08.017 (English, researchgate.net [PDF; 5.4 MB ; accessed on October 10, 2018]).
  19. ↑ EM Epstein, VN Basmanov, LA Berezina, TL Gol'dfurt, LN Zhuravleva, EA Nechaeva, SV Sokolov, LV Chernyshova: The appropriateness of allocation, the mineralogical and geochemical features and valuation of iron-phosphorus and rare-metal ores of the Kovdor deposit . In: Report about scientific works . Mineralogical Society Series. 1st edition. tape 1 . Archives of the Geological Institute of the Kola Science Center of RAN, Moscow 1970, p. 1–217 (Russian).