Isolue hit

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Isolue hit
Isolueshite-614289.jpg
Isolueshite crystal from the Kirovsky Mine (Kirovskii Apatite Mine), Kukiswumtschorr (Kukisvumchorr), Chibinen , Kola Peninsula , Russia
General and classification
other names
chemical formula
  • NaNbO 3
  • Na (Nb, Ti) O 3
  • (Na, Ca, La) (Nb, Ti) O 3
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		4.CC.35
04.03.03.06
Crystallographic Data
Crystal system cubic
Crystal class ; symbol cubic hexakisoctahedral; 4 / m  3  2 / m
Space group Pm 3 m (No. 221)Template: room group / 221
Lattice parameters a  = 3.909 (1)  Å
Formula units Z  = 1
Physical Properties
Mohs hardness 5.5 (VHN 70 average 580)
Density (g / cm 3 ) measured: 4.72 (1); calculated: 4.69
Cleavage is missing
Break ; Tenacity uneven; brittle
colour brownish black
Line color light yellow
transparency opaque to slightly translucent
shine Diamond luster

Isolueshit is a very rare occurring mineral from the mineral class of "oxides and hydroxides" with the idealized chemical composition NaNbO 3 and chemically seen a sodium - niobium - oxide or sodium niobate . However, since usually a small part of the sodium in natural Isolueshiten by calcium and / or various rare earth metals (especially here lanthanum ) and a part of niobium by titanium replaced ( substituted ) which is a chemical formula in a variety of sources with ( Na, Ca, La) (Nb, Ti) O 3 indicated.

Isolueshite crystallizes in the cubic crystal system and seldom develops idiomorphic , occasionally also fused crystals up to about 0.3 mm in size, enclosed in microcline and sodalite . The surfaces of the opaque, brownish-black crystals have a diamond-like sheen .

Etymology and history

Isolueshite was first discovered in the apatite mine Kirow (also Kirovsky or Kirovskii , Russian Кировский рудник ) on Kukiswumtschorr (Kukisvumchorr) in the Chibinen on the Russian Kola Peninsula . It was first described in 1997 by Anton Chakhmouradian, Viktor Yakovenchuk, Roger H. Mitchell and Alla Bogdanova, who called the mineral an isolueshit based on its cubic (isometric) structure or optical isometry and its close relationship with syphilis .

The type material of Isolueshit is in the mining museum of the mining institute under the catalog no. 3007 and kept in the Mineralogical Museum of the State University of Saint Petersburg under catalog number 1/18271 in Saint Petersburg .

classification

Since the isolue hit was only recognized as an independent mineral in 1995 and this was published in 1997, it is not listed in the outdated 8th edition of the mineral classification according to Strunz . Only in the "Lapis mineral directory", which was last updated 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 received the system and mineral number. IV / C.10-55 . In the "lapis system" this corresponds to the class of "oxides and hydroxides" and there the department "oxides with ratio metal: oxygen = 2: 3 (M 2 O 3 & relatives)", where isolueshite together with barioperovskite , lakargiite , Latrappit , loparite , Lueshit , Macedonit , Megawit , Natroniobit , Pauloabibit , perovskite , Tausonit and Vapnikit forms the "perovskite series".

The 9th edition of Strunz's mineral systematics, which has been valid since 2001 and updated by the International Mineralogical Association (IMA) until 2009, assigns isolueshite to the oxides division with the molar ratio "metal: oxygen = 2: 3, 3: 5 and comparable" a. This is further subdivided according to the relative size of the cations involved , so that the mineral can be found according to its composition in the sub-section "With large and medium-sized cations", where together with loparite (Ce) , Macedonite and Tausonit the "Loparite- Macedonit Group "with the system no. 4.CC.35 forms.

Also the systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns isolueshite to the class of "oxides and hydroxides" and there in the department of "oxides". Here it is together with barioperovskite, lakargiite, latrappite, loparite- (Ce), lueshite, perovskite and tauonite in the " perovskite group " with the system no. 04.03.03 to be found in the subsection “Simple oxides with a cation charge of 3+ (A 2 O 3 )”.

Chemism

The theoretical composition of pure isolueshite (NaNbO 3 ) consists of 14.027% by weight sodium (Na), 56.687% by weight niobium (Nb) and 29.286% by weight oxygen (O).

However, the analysis of the type material also revealed foreign admixtures of titanium (Ti), calcium (Ca), strontium (Sr), thorium (Th) and the rare earths lanthanum (La) and cerium (Ce) as well as traces of potassium (K) and tantalum (Ta) and the rare earths praseodymium (Pr), neodymium (Nd) and samarium (Sm). On the basis of three oxygen ions, the average empirical composition (Na 0.73 Ca 0.08 La 0.05 Ce 0.03 Sr 0.03 Th 0.01 ) Σ = 0.93 (Nb 0.66 Ti 0.35 ) Σ = 1.01 O 3.00 calculated and idealized to the formula (Na, Ca, La) (Nb, Ti) O 3 .

Crystal structure

Isolueshite crystallizes cubically in the space group Pm 3 m (space group no. 221) with the lattice parameter a  = 3.909 (1)  Å and one formula unit per unit cell . Template: room group / 221

properties

In contrast to its brownish-black surface color , isolueshite appears bluish in the incident light microscope with internal reddish-brown reflections.

The microhardness of Isolueshit is used at a test load of 70 g and 616 to 544 {interlocutory 110} and {100} after 479-544. This corresponds to an average Vickers hardness of 580 and a Mohs hardness of 5.5.

Modifications and varieties

The compound NaNbO 3 is trimorphic and occurs in nature in addition to the cubic crystallizing isoluesite as orthorhombic crystallizing syphilis and as trigonal crystallizing pauloabibite ; possibly also as monoclinic crystallizing natroniobite , although its mineral status is still questionable.

Education and Locations

Isolueshit formed in hydrothermally converted pegmatite - veins in urtitischem rock, a luminous plutonic , feldspatfreien rock of the family of Ijolith -Gesteine. In addition to microcline and sodalite, in which isolueshite can usually be found as an inclusion , aegirine , arfvedsonite and lamprophyllite appear as accompanying minerals .

Apart from its type locality , the apatite mine Kirow on the Kola Peninsula in Russia, no other location for isolueshite is known (as of 2019).

See also

literature

  • Anton Chakhmouradian, Viktor Yakovenchuk, Roger H. Mitchell, Alla Bogdanova: Isolueshite: a new mineral of the perovskite group from the Khibina alkaline complex . In: European Journal of Mineralogy . tape 9 , 1997, pp. 483–490 (English, available online at rruff.info [PDF; 1,2 MB ; accessed on March 17, 2019]).
  • John Leslie Jambor , Edward S. Grew, Andrew C. Roberts: New mineral names . In: American Mineralogist . tape 83 , 1998, pp. 186 (English, available at rruff.info [PDF; 79 kB ; accessed on March 17, 2019]).
  • Sergey V. Krivovichev, Anton R. Chakhmouradian, Roger H. Mitchell, Stanislav K. Filatov, Nikita V. Chukanov: Crystal structure of isolueshite and its synthetic compositional analogue . In: European Journal of Mineralogy . tape 12 , no. 3 , 2000, pp. 597-607 , doi : 10.1127 / ejm / 12/3/0597 (English).
  • Roger H. Mitchell, Mark D. Welch, Anton R. Chakhmouradian: Nomenclature of the perovskite supergroup: A hierarchical system of classification based on crystal structure and composition . In: Mineralogical Magazine . tape 81 , no. 3 , 2017, p. 411–461 (English, available at rruff.info [PDF; 2.2 MB ; accessed on March 17, 2019]).

Web links

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

Individual evidence

  1. ↑ a b c d Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: September 2019. (PDF 2672 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, September 2019, accessed October 3, 2019 .
  2. ↑ a b c 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 .
  3. ↑ a b c d 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.  201 (English).
  4. ↑ a b c d e f g h i Anton Chakhmouradian, Viktor Yakovenchuk, Roger H. Mitchell, Alla Bogdanova: Isolueshite: a new mineral of the perovskite group from the Khibina alkaline complex . In: European Journal of Mineralogy . tape 9 , 1997, pp. 483–490 (English, available online at rruff.info [PDF; 1,2 MB ; accessed on March 17, 2019]).
  5. ↑ David Barthelmy: Isolueshite Mineral Data. In: webmineral.com. Retrieved October 3, 2019 .
  6. ↑ Catalog of type mineral specimens - I. (PDF 28 kB) In: smmp.net. Commission on Museums (IMA), December 12, 2018, accessed March 17, 2019 (English, Isolueshite p. 4).
  7. ↑ 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 3, 2019 .
  8. Jump up ↑ John Leslie Jambor , Edward S. Grew, Andrew C. Roberts: New mineral names . In: American Mineralogist . tape  83 , 1998, pp. 186 (English, available at rruff.info [PDF; 79 kB ; accessed on March 17, 2019]).
  9. ↑ Find location list for isolueshite at the Mineralienatlas and at Mindat