Leningradit

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Leningradit
General and classification
other names

IMA 1988-014

chemical formula
  • PbCu 3 (VO 4 ) 2 Cl 2
  • PbCu 3 [Cl | VO 4 ] 2
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates
System no. to Strunz
and to Dana 		8.BH.65
05.41.17.01
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol orthorhombic-dipyramidal; 2 / m  2 / m  2 / m
Space group Ibam (No. 72)Template: room group / 72
Lattice parameters a  = 9.005 (7)  Å ; b  = 11.046 (9) Å; c  = 9.349 (7) Å
Formula units Z  = 4
Physical Properties
Mohs hardness 4 to 4.5; 4.25 ( VHN 10  = 180-345)
Density (g / cm 3 ) measured: 4.81; calculated: 4.97
Cleavage completely after {010}
Break ; Tenacity brittle
colour light red, reddish brown; also golden red in transmitted light
Line color Orange red
transparency opaque, transparent in very thin grains
shine Glass gloss
Crystal optics
Optical character biaxial negative

Leningradite is a very rarely occurring mineral from the mineral class of "phosphates, arsenates and vanadates" with the idealized chemical composition PbCu 3 (VO 4 ) 2 Cl 2 or in the crystal chemical structural formula notation PbCu 3 [Cl | VO 4 ] 2 . From a chemical point of view, the mineral is therefore a lead - copper - vanadate with additional chlorine ions .

Leningradite crystallizes in the orthorhombic crystal system , but only develops tiny, coarsely crystalline, tabular rhombuses and flakes up to about 0.3 mm in size as well as radial to spherical mineral aggregates of light red to reddish brown color with a glass-like sheen on the surfaces. The mineral is generally opaque and only in very thin grains (<0.02 mm) transparent with a golden red color. Leningradit leaves an orange-red line on the whiteboard .

Etymology and history

Leningradit was first discovered in the Fumarolenprodukten the volcano Tolbachik , more precisely on the southwestern ridge of the second cinder cone on the peninsula of Kamchatka in Russia's Far Eastern Federal District . The mineral samples with the newly discovered mineral were during the great fissure eruption ( Great Fissure collected) from 1975 to 1976 on the north breakthrough.

After the mineral was examined and recognized by the International Mineralogical Association (internal entry number of the IMA: 1988-014 ), the first description was published in 1990 by Lidiya P. Vergasova, Stanislav K. Filatov, TF Semenova and VV Anan'yev, the named the mineral after the then name of the city of Saint Petersburg (1924 to 1991 Leningrad ). The type material of the mineral was also found in the Mining Museum of Saint Petersburg under the collection no. Deposited in 2003/1 .

classification

Since Leningradite was only recognized as an independent mineral in 1988, it is not yet listed in the 8th edition of the Strunz mineral classification, which has been outdated since 1977 . Only in the Lapis mineral directory , which was revised and updated in 2018 by Stefan Weiß, which is still based on this classic system from Karl Hugo Strunz out of consideration for private collectors and institutional collections , the mineral received the system and mineral number. VII / B.28-60 . In the "Lapis system" this corresponds to the class of "phosphates, arsenates and vanadates" and there the section "Anhydrous phosphates, with foreign anions F, Cl, O, OH", where Leningradite together with Bertossaite , Palermoite , Natropalermoite , Peatite (Y) - , Ramikit- (Y) , Attakolith , Sewardit , Crimsonit , Karminit , Namibit , Paganoit , Khorixasit forms a separate, but unnamed group / the "group".

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, also assigns Leningradite to the category of “phosphates etc. with additional anions; without H 2 O “. However, this is further subdivided according to the relative size of the cations involved and the molar ratio of the additional anions to the phosphate, arsenate or vanadate complex, so that the mineral is classified in the sub-section “With medium-sized and mostly large cations; (OH etc.): RO 4  = 1: 1 “can be found where it is the only member of the unnamed group 8.BH.65 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Leningradite to the class of "phosphates, arsenates and vanadates" and there to the category of "anhydrous phosphates, etc., with hydroxyl or halogen". Here he is to be found as the only member of the unnamed group 41.05.17 within the subsection “Anhydrous phosphates etc., with hydroxyl or halogen with (AB) 2 (XO 4 ) Z q ”.

Chemism

Using 10 microprobe analyzes on five Leningradite grains, an average composition of 32.13% PbO , 32.84% CuO , 0.32% ZnO , 26.22% V 2 O 5 , 0.49% As 2 O 5 , 9.60% Cl and 2.17% O  ≡ Cl 2 were determined. Assuming 10 parts of O + Cl, this corresponds to the empirical formula Pb 1.01 (Cu 2.89 Zn 0.05 ) Σ = 2.94 [(V 1.01 As 0.01 ) Σ = 1.02 O 4 ] 2 (Cl 1.90 O 0.10 ) Σ = 2.00 , which was idealized to PbCu 3 (VO 4 ) 2 Cl 2 .

Crystal structure

Leningradite crystallizes orthorhombically in the space group Ibam (space group no. 72) with the lattice parameters a  = 9.005 (7)  Å ; b  = 11.046 (9) Å; c  = 9.349 (7) Å and 4 formula units per unit cell . Template: room group / 72

properties

Leningradite is insoluble in water. In air it is stable up to 425 ± 25 ° C; beyond that it breaks down to vanadinite (Pb 5 (VO 4 ) 3 Cl) and some by-products.

Education and Locations

Leningradite forms as a volcanic sublimation product at a temperature of around 140 ° C. Anglesite , hematite , lammerite and tolbachite occur here as accompanying minerals .

Apart from its type locality on the Tolbatschik volcano in the Far East of Russia, the mineral has so far only been discovered in the Krennbruch , a granite and pegmatite quarry near Matzersdorf in the Saldenburg municipality (Freyung-Grafenau district) in Germany (as of 2019).

See also

literature

  • Lidiya P. Vergasova, Stanislav K. Filatov, TF Semenova, VV Anan'yev: Leningradite PbCu 3 (VO 4 ) 2 Cl 2 , a new mineral from volcanic exhalations . In: Doklady Akademii Nauk SSSR . tape 310 , no. 6 , 1990, pp. 1434–1437 (English, rruff.info [PDF; 253 kB ; accessed on November 27, 2019]).
  • John Leslie Jambor , David A. Vanko: New mineral names . In: American Mineralogist . tape 76 , 1991, pp. 1434–1440 (English, rruff.info [PDF; 918 kB ; accessed on November 27, 2019]).
  • Oleg I. Siidra, Sergey V. Krivovichev, Thomas Armbruster , Stanislav K. Filatov, Igor V. Pekov: The crystal structure of leningradite, PbCu 3 (VO 4 ) 2 Cl 2 . In: The Canadian Mineralogist . tape 45 , 2007, p. 445–449 , doi : 10.2113 / gscanmin.45.3.445 (English, [2] [PDF; 999 kB ; accessed on November 27, 2019]).

Web links

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 November 2, 2019 .
  2. ^ A b 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.  460 (English).
  3. ↑ a b c Oleg I. Siidra, Sergey V. Krivovichev, Thomas Armbruster , Stanislav K. Filatov, Igor V. Pekov: The crystal structure of leningradite, PbCu 3 (VO 4 ) 2 Cl 2 . In: The Canadian Mineralogist . tape 45 , 2007, p. 445–449 , doi : 10.2113 / gscanmin.45.3.445 (English, [1] [PDF; 999 kB ; accessed on November 27, 2019]).
  4. ↑ a b c d 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 .
  5. ↑ a b c d e f g Leningradite . 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; 66  kB ; accessed on November 2, 2019]).
  6. ↑ a b Lidiya P. Vergasova, Stanislav K. Filatov, TF Semenova, VV Anan'yev: Leningradite PbCu 3 (VO 4 ) 2 Cl 2 , a new mineral from volcanic exhalations . In: Doklady Akademii Nauk SSSR . tape 310 , no. 6 , 1990, pp. 1434–1437 (English, rruff.info [PDF; 253 kB ; accessed on November 27, 2019]).
  7. ↑ Catalog of Type Mineral Specimens - L. (PDF 70 kB) In: docs.wixstatic.com. Commission on Museums (IMA), December 12, 2018, accessed August 29, 2019 .
  8. ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed November 2, 2019 .
  9. ↑ List of localities for Leningradite in the Mineralienatlas and Mindat , accessed on November 2, 2019.