Berzeliite

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Berzeliite
Berzeliite-661693.jpg
Yellow berzeliite in calcite from Långban , Sweden (field of view 14 mm)
General and classification
other names

Berzelite, Kühnit, Magnesium-Berzeliite, Magnesium-Pharmacolite

chemical formula Ca 2+ 2 Na + Mg 2+ 2 As 5+ 3 O 12
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates
System no. to Strunz
and to Dana 		8.AC.25 ( 8th edition : 7 / A.08-50)
38.2.1.1
Crystallographic Data
Crystal system cubic
Crystal class ; symbol cubic hexakisoctahedral; 4 / m  3  2 / m
Space group Ia 3 d (No. 230)Template: room group / 230
Lattice parameters a  = 12.33 (synthetic end
link ) 12.3450 (natural mixed crystal)  Å
Formula units Z  = 8
Physical Properties
Mohs hardness 5 - 6
Density (g / cm 3 ) natural mixed crystal: 4.06 (calculated)
Cleavage not observed
Break ; Tenacity shell-like
colour colorless (synthetic), dirty white to honey yellow, orange (natural mixed crystal)
Line color Please complete!
transparency Please complete!
shine Wax gloss
Crystal optics
Refractive index n  = 1.710 (synthetic)
Birefringence isotropic
Other properties
Chemical behavior soluble in nitric acid

The mineral berzeliite is a very rare arsenate from the garnet group and has the idealized chemical composition Ca 2+ 2 Na + Mg 2+ 2 As 5+ 3 O 12 . It crystallizes in the cubic crystal system with the structure of garnet.

Berzeliite occurs in the form of waxy, coarse masses and crusts or mostly xenomorphic crystals rarely larger than a millimeter in size. The color varies with increasing manganese content from colorless to yellow, orange to brownish.

Berzeliite is formed during the contact metamorphosis of carbonate sediments by granitic to dioritic magmas . The type locality is the extremely mineral-rich iron-manganese skarn deposit Långban in the municipality of Filipstad , Värmland County , Sweden .

Etymology and history

Jöns Jakob Berzelius not only discovered the element selenium , but was also the first to characterize the Berzelianite von Skrikerum, later named after him, as copper selenide.

The first description of this new type of arsenate from Långban (Langbanshytta) was given by Professor OB Kühn from Leipzig in 1840. He did not determine the composition quite correctly with (Ca, Mg, Mn) 3 As 2 O 8 and named the mineral after the Swedish medic and Chemist Jöns Jakob Berzelius Berzeliit. This made Berzeliite the second mineral to be named after the famous chemist. As early as 1832, François Sulpice Beudant renamed the séleniure de cuivre he had previously described in Berzelin . In 1850 the name Berzelin was changed again to Berzelianit by James Dwight Dana .

Obviously the choice of the name Berzeliit was not without controversy

I made this suggestion, not out of common flattery, which I hate from the bottom of my heart, but imbued with true, sincere, but not blind, respect and admiration for Bezelius;

and had been delayed for a few years due to personal problems:

If I only come forward with the present communication, I have only to deplore the unfavorable conditions which have hindered the acceleration and completion of a rather extensive series of investigations into mineral bodies in which the Berzelite formed a part ...

The structure was determined by the Austrian mineralogist Felix Machatschki 90 years later during his stay in Göttingen . He was able to show that sodium is an essential component of berzeliite, that berzeliite crystallizes with the structure of garnet and derived the correct composition from this: Ca 2+ 2 Na + Mg 2+ 2 As 5+ 3 O 12 .

In the same year Machatschki was appointed professor at the University of Tübingen , where he and Wolfgang Bubeck provided the final proof of the isotype of berzeliite and garnet in 1935 . It was the first ever evidence of an isotype of an arsenate with a silicate structure.

The first syntheses were carried out in 1968 by Jun Ito from the Department of Geological Sciences at Harvard University in Cambridge (Massachusetts) . He was able to show that berzeliite and its manganese equivalent (manganese berzeliite) are completely miscible and no longer stable at temperatures above 550 ° C (1.5 kbar).

In 1995, Khorari and co-workers were able to show with further investigations on synthetic arsenate grenades that berzeliite is polymorphic and changes into the structure of alluaudite at high temperatures .

classification

The current classification of the International Mineralogical Association (IMA) counts the berzeliite to the garnet upper group, where together with manganese berzeliite , palenzonaite and shepherdite it forms the berzeliite group with 15 positive charges on the tetrahedrally coordinated lattice position.

In the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the berzeliite belongs to the mineral class of "phosphates, arsenates and vanadates" and there to the division of "anhydrous phosphates [PO 4 ] 3− , without foreign anions", where it together with Palenzonait , Chladniit , Fillowit , Galileiit , Johnsomervilleit , Manganberzeliit , Schäferit , Storneseit- (Y) and Xenophyllit the unnamed group VII / A.08 forms.

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 assigns Berzeliite to the category of “phosphates etc. without additional anions; without H 2 O “. This is, however, further subdivided according to the relative size of the cations involved , so that the mineral can be found according to its composition in sub-section C "With medium-sized and large cations", where with palenzonaite, manganese berzelite and schäferite it is the berzeliite group 8.AC.25 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Berzeliite to the class of "phosphates, arsenates and vanadates" and there in the department of "anhydrous phosphates etc.". Here it is together with palenzonaite, manganese berzelite and schäferite in the Berzeleiite group of minerals according to Dana / Phosphate, Arsenate, Vanadate # 38.02.01 Berzeliite group within the subdivision "38.02 Anhydrous phosphates etc., (A + B 2+ ) 5 (XO 4 ) 3 ”.

Chemism

Berzeliite with the idealized composition [X] (Na + Ca 2+ 2 ) [Y] Mg 2+ 2 [Z] As 5+ 3 O 12 is the magnesium analog of manganese berzeliite ( [X] (Na + Ca 2+ 2 ) [Y] Mn 2+ 2 [Z] As 5+ 3 O 12 ) or the arsenic analogue of schäferite ( [X] (Na + Ca 2+ 2 ) [Y] Mg 2+ 2 [Z] V 5 + 3 O 12 ). The position of the cations in the garnet structure is indicated in the square brackets.

The following composition is given for berzeliite from the type locality:

  • [X] (Ca 2+ 2.13 Na + 0.90 ) [Y] (Mg 2+ 1.68 Mn 2+ 0.29 ) [Z] (As 5+ 2.89 V 5+ 0.02 P 5+ 0.02 Si 4+ 0.07 ) O 12

The only significant deviation from the ideal composition is the replacement of magnesium by manganese on the octahedral Y-position, corresponding to the exchange reaction

  • [Y] Mg 2+ = [Y] Mn 2+

There is complete interchangeability of Mg and Mn in this position.

The calcium content in the X position can be slightly above the maximum value to be expected for grenades in this group. The charge balance takes place by incorporating Si on the tetrahedral position according to an exchange reaction - [X] Na + + [Z] As 5+ = [X] Ca 2+ + [Z] Si 4+

Crystal structure

Berzeliite crystallizes with cubic symmetry in the space group Ia 3 d (space group no. 230) with 8 formula units per unit cell . The natural mixed crystal from the type locality has the lattice parameter a  = 12.3450  Å . The lattice parameter of synthetic, pure Berzeliite is slightly smaller: a  = 12.33 Å. Template: room group / 230

The structure is that of garnet . Sodium (Na + ) and calcium (Ca 2+ ) occupy the dodecahedral X position surrounded by 8 oxygen ions, magnesium (Mg 2+ ) the octahedral Y position surrounded by 6 oxygen ions and the tetrahedral Z position surrounded by 4 oxygen ions is exclusive occupied with arsenic (As 5+ ).

Education and Locations

Berzeliite is formed during the metamorphosis of iron-manganese deposits.

The type locality is the Långban iron-manganese skarn deposit in Filipstad municipality , Värmland County , Sweden . Berzeliite occurs here in manganese-rich skarns together with calcite and hausmannite , and more rarely with magnetite or Richterite . This extremely mineral-rich manganese deposit is the type locality of over 70 other, mostly very rare minerals.

Another, similar deposit in Sweden is the Sjögruvan Mine near Grythyttan in the municipality of Hällefors , also in the province of Örebro County, Sweden.

In Italy, berzeliite is found in the metamorphic manganese deposits of the province of Cuneo in Piedmont . In the Montaldo mine near Borgata Oberti in the Corsaglia valley in the municipality of Montaldo di Mondovì , berzeliite occurs ingrown with calcite. Berzeliite was also found on heaps in the Valletta mine in the Miara Valley in the municipality of Canosio .

In Switzerland , Berzeliite was found on the dumps of the Falotta mine in the municipality of Surses in the Albula Valley , Graubünden .

In the Arsenatnaya fumarole on the northern breakthrough of the "Great Fissure eruption" of the volcano Tolbachik in Kamchatka , Russia , occurs Berzeliit on along with numerous, very rare arsenate.

See also

Web links

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

Individual evidence

  1. ↑ a b c d Felix Machatschki: IX. Berzeliite, an arsenate of the formula and structure type garnet (X3 Y2 Z3 O12) . In: Journal of Crystallography - Crystalline Materials . tape 73 , 1930, pp. 123-140 , doi : 10.1524 / zkri.1930.73.1.123 .
  2. ↑ a b c d e f g Jun Ito: SYNTHESIS OF THE ERZBLIITE (Ca 2 NaMg 2 As 3 O 12 ) -MANGANESEBERZELITE (Ca2NaMn2As3O12) SERIES (ARSENATE GARNET) . In: American Mineralogist . tape 53 , 1968, pp. 316–319 ( minsocam.org [PDF; 241 kB ; accessed on April 4, 2018]).
  3. ↑ a b c d e f M. Nagashima, and T. Armbruster: Palenzonaite, berzeliite, and manganberzeliite: (As5 +, V5 +, Si4 +) O4 tetrahedra in garnet structures . In: Mineralogical Magazine . tape 76 , 2012, p. 1081-1097 ( rruff.info [PDF; 379 kB ; accessed on March 23, 2018]).
  4. ↑ a b c d e f g h i j k l m OB Kühn: New mineral from Langbanshytta near Fahlun . In: Annals of Chemistry and Pharmacy . tape 34 , 1840, p. 211–218 ( rruff.info [PDF; 574 kB ; accessed on April 4, 2018]).
  5. ↑ a b c W. Bubeck and F. Machatschki: The crystal structure of berzeliite (Ca, Na) 3 (Mg, Mn) 2 [AsO 4 ] 3 . In: Journal of Crystallography - Crystalline Materials . tape 90 , 1935, pp. 44–50 ( rruff.info [PDF; 3.2 MB ; accessed on April 4, 2018]).
  6. ^ A b Hawthorne FC: Refinement of the Crystal Structure of Berzeliite . In: Acta Cryst. B32, 1976, p. 1581–1583 ( researchgate.net [PDF; 319 kB ; accessed on April 4, 2018]).
  7. ↑ a b c Photos by Berzeliit. In: mindat.org. Hudson Institute of Mineralogy, accessed May 2, 2020 .
  8. ↑ a b c d e f Find location list for Berzeliite from the Mineralienatlas and Mindat , accessed on May 2, 2020.
  9. ^ François Sulpice Beudant : Traité Élémentaire de Minéralogie Vol. II . 2nd Edition. Verdière, Paris 1832, p.  534 ( limited preview in Google Book search).
  10. ^ Felix Machatschki: XXIV. Shorter original communications and notes: About Berzeliit . In: Journal of Crystallography - Crystalline Materials . tape 74 , 1930, pp. 230-236 , doi : 10.1524 / zkri.1930.74.1.230 .
  11. ↑ S. Khorari, A. Rulmont, R. Cahay, P. Tarte: Structure of the Complex Arsenates NaCa 2 M 2+ 2 (AsO 4 ) 3 (M 2+ = Mg, Ni, Co): First Experimental Evidence of a Garnet-Alluaudite Reversible Polymorphism . In: Journal of Solid State Chemistry . tape 118 , 1995, pp. 267-273 , doi : 10.1006 / jssc.1995.1343 .
  12. ^ Edward S. Grew, Andrew J. Locock, Stuart J. Mills, Irina O. Galuskina, Evgeny V. Galuskin and Ulf Hålenius: IMA Report - Nomenclature of the garnet supergroup . In: American Mineralogist . tape 98 , 2013, p. 785-811 ( cnmnc.main.jp [PDF; 2,3 MB ; accessed on July 8, 2017]).
  13. ^ GC Piccoli, U. Kolitsch, G. Blass, ME Ciriotti: Berzeliite di Montaldo di Mondovì: prima segnalazione italiana. In: Micro (UK report) . tape 1 , 2007, p. 49–54 ( researchgate.net [PDF; 135 kB ; accessed on April 11, 2018]).