Lotharmeyerite

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Lotharmeyerite
Lotharmeyerite3.jpg
Lotharmeyerite crystals up to 0.3 mm in size on chalcophanite from the "Mina Ojuela" near Mapimí , Municipio de Mapimí , Durango , Mexico
General and classification
other names

IMA 1982-060

chemical formula
  • Ca (Zn, Mn 3+ ) 2 (AsO 4 ) 2 (H 2 O, OH)
  • Ca (Mn 3+ , Zn) 2 (AsO 4 ) 2 (OH, H 2 O)
  • CaZnMn 3+ (As 5+ O 3 OH) 2 (OH) 3
  • CaZnMn +3 (AsO 4) 2 (OH) • 2H 2 O
  • CaZnMn 3+ [(OH, H 2 O) 2 | (AsO 4 ) 2 ]
Mineral class
(and possibly department) 		Phosphates, arsenates, vanadates
System no. to Strunz
and to Dana 		8.CG.15 ( 8th edition : VII / C.31)
01/37/06/01
Similar minerals Manganese solder armyerite, cobalt solder armyerite
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group C 2 / m (No. 12)Template: room group / 12
Lattice parameters a  = 9.0727  Å ; b  = 6.2530 Å; c  = 7.4150 Å
β  = 116.739 °
Formula units Z  = 2
Physical Properties
Mohs hardness ≈ 3
Density (g / cm 3 ) 4.2 (measured); 4.186 (calculated)
Cleavage not observed
Break ; Tenacity uneven; brittle
colour dark reddish-orange, yellow-brown, reddish-flesh-colored
Line color pale orange
transparency not specified, probably translucent
shine Glass gloss
Crystal optics
Refractive index n  = 1.80
Pleochroism strong from X = Z = light pink orange to Y = dark reddish orange
Other properties
Chemical behavior Slightly soluble in oxalic acid, HCl and H 2 SO 4 , dissolution in immersion liquids

Lotharmeyerite is a very rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the monoclinic crystal system with the chemical composition Ca (Zn, Mn 3+ ) 2 (AsO 4 ) 2 (H 2 O, OH) and is therefore chemically a water-containing calcium - zinc - manganese - arsenate with a variable proportion of additional Hydroxide ions .

Lotharmeyerite develops crusts of isometric microcrystals at its type locality, which sit on the characteristic purple adamin and the accompanying matrix. The type locality of the mineral is the "Mina Ojuela" near Mapimí , Municipio de Mapimí , Durango , Mexico .

Etymology and history

Julius Lothar von Meyer - namesake for Lotharmeyerite

In early 1982, the amateur mineralogist Curt Segeler from Brooklyn, New York, presented custodian Pete J. Dunn of the Smithsonian Institution with dark reddish-orange crusts that contained the then just-discovered light purple Adamin crystals from the 6th level of the "San Judas ore vent" the “Mina Ojuela” at Mapimí and its matrix covered. The first investigations already made sure that it was a new mineral. After further investigation, the new mineral was presented to the International Mineralogical Association (IMA), which recognized it in 1982. Pete J. Dunn of the Smithsonian Institution described it as lotharmeyerite in The Mineralogical Record in 1983. The author named the mineral after the German doctor and chemist Julius Lothar von Meyer (1830–1895), next to Dmitri Mendeleev one of the founders of the periodic table of chemical elements.

The type material for Lotharmeyerite (holotype) comes from a donation by Curt Segeler and is stored under catalog number 149482 in the collection of the National Museum of Natural History , Washington, DC , USA , which is part of the Smithsonian Institution .

Unfortunately, the lotharmeyerite crystals present to Pete Dunn were both too tiny and too sparse to be fully characterized. Fortunately, larger crystals suitable for single crystal investigations were discovered in the "Mina Ojuela" as early as 1983, on which Anthony R. Kampf, James E. Shigley and George R. Rossman were able to carry out much more detailed investigations and determine the properties missing in the original description. They also published their results in 1984 in the Mineralogical Record. However, after the discovery and first description of the new mineral manganese solder armyerite from the "Starlera" mine near Ferrera GR in Val Ferrera , Hinterrhein , Graubünden , Switzerland in 2002 by a team of scientists led by the Swiss-Australian mineralogist Joël Brugger, it became clear that the Lotharmeyerite crystals from the "Mina Ojuela" described in 1984 actually represent representatives of the new mineral manganese soldering agentite. In order to differentiate the two minerals Lotharmeyerite and Manganlotharmeyerite from one another, Lotharmeyerite was redefined at the same time. In contrast, the ferrilotharmeyerite described by Kurt Walenta in 2002 has proven to be Lotharmeyerite sensu stricto.

classification

The current classification of the International Mineralogical Association (IMA) counts lotharmeyerite to the tsumcorite group with the general formula Me (1) Me (2) 2 (XO 4 ) 2 (OH, H 2 O) 2 , in which Me (1), Me (2) and X different positions in the structure of the minerals of the tsumcorite group with Me (1) = Pb 2+ , Ca 2+ , Na + , K + and Bi 3+ ; Me (2) = Fe 3+ , Mn 3+ , Cu 2+ , Zn 2+ , Co 2+ , Ni 2+ , Mg 2+ and Al 3+ and X = As 5+ , P 5+ , V 5+ and represent S 6+ . To Tsumcoritgruppe include not only Lotharmeyerit still Cabalzarit , Cobaltlotharmeyerit , Cobalttsumcorit , Ferrilotharmeyerit , Gartrellit , Helmutwinklerit , Kaliochalcit , Krettnichit , Lukrahnit , Manganlotharmeyerit , Mawbyit , Mounanait , Natrochalcit , Nickellotharmeyerit , Nickelschneebergit , Nickeltsumcorit , Phosphogartrellit , Rappoldit , Schneebergit , Thometzekit , Tsumcorit , Yancowinnait and Zinc Gartrellite . Lotharmeyerite together with cabalzarite ( Me (2) = Mg), cobaltlotharmeyerite (Co), lotharmeyerite (Zn), manganese solderarmyerite (Mn 3+ ) and nickellotharmeyerite (Ni) form the "Lotharmeyerite subgroup" named after Lotharmeyerite.

In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , Lotharmeyerite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "water-containing phosphates without foreign anions ", where it belongs together with Cabalzarite, Cobaltlotharmeyerite and Cobalt Sumcorite , Ferrilotharmeyerit, Gartrellite, Helmutwinklerit, Krettnichit, Lukrahnit, Manganlotharmeyerit, Mawbyit, Mounanait, Nickellotharmeyerit, Nickelschneebergit, Phosphogartrellite, Rappoldit, Schneebergit, Thometzekit, Tsumcorit-Nr. Gartrellit-Nr. VII / C.31 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 assigns Lotharmeyerite to the category of “phosphates etc. without additional anions; with H 2 O “. However, this is further subdivided according to the relative size of the cations involved and the molar ratio of phosphate, arsenate or vanadate complex to the water of crystallization content , so that the mineral can be classified according to its composition in the subsection “With large and medium-sized cations; RO 4  : H 2 O = 1: 1 "is to be found, where together with cabalzarite, cobalt solder armyerite, cobalt sumcorite, ferrilotharmeyerite, krettnichite, manganese solder armyerite, mawbyite, mounanaite, nickellotharmeyerite, nickel snow mountainite, snow mountainite", Thometzekit and tsumcorite with the tsumcorite group System no. 8.CG.15 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Lotharmeyerite to the class of "phosphates, arsenates and vanadates" and there to the department of "phosphate minerals". Here it is together with Ferrilotharmeyerit, Cobaltlotharmeyerit and Nickellotharmeyerit in the " Lotharmeyerit series " with the system no. 37.01.06 to be found in the subsection of "Anhydrous acidic phosphates etc., with various formulas".

Chemism

Fourteen microprobe analyzes on Lotharmeyerite resulted in mean values ​​of 13.55% Mn 2 O 3 ; 16.55% ZnO; 1.18% CaO; 0.02% K 2 O; 47.63% As 2 O 3 and 5.80% H 2 O + . On the basis of ten oxygen atoms , the empirical formula Ca 0.99 (Zn 1.01 Mn 3+ 0.85 ) Σ = 1.86 (As 1.03 O 4 ) 2 [(OH) 0, 85 , 1.17H 2 O], which leads to Ca 1.00 (Zn 1.02 Mn 3+ 0.98 ) (As 1.00 O 4 ) 2 [(OH) 0.98 , 1.04H 2 O] refined and idealized to Ca (Zn, Mn 3+ ) (AsO 4 ) 2 (H 2 O, OH) 2 .

Lotharmeyerite is the Zn-dominant analogue of the Mn 3+ -dominated manganese soldering agent, with which it forms a complete mixed crystal row . It is also the corresponding analogue to the Mg-dominated Cabalzarite, to the Fe 3+ -dominated Ferrilotharmeyerite, to the Co-dominated Cobaltlotharmeyerite and to the Ni-dominated Nickelotharmeyerite.

Crystal structure

Lotharmeyerite crystallizes in the monoclinic crystal system in the space group C 2 / m (space group no. 12) with the lattice parameters a  = 9.0727  Å ; b  = 6.2530 Å; c  = 7.4150 Å and β = 116.739 ° as well as two formula units per unit cell . Template: room group / 12

The crystal structure of the Lotharmeyerits is made of stretched by [001], rutile -like chains of M O 6 - octahedra (Symmetry 1 formed) obtained by X O 4 - tetrahedron (symmetry 2 / m ) and hydrogen bonds are connected and [ M 2 ( X O 4 ) 2 (OH, H 2 O) 2 ] layers form parallel (001). These layers are linked to one another by the larger A cations (symmetry 2 / m ) and other hydrogen bonds. There are two hydrogen bonds, one with O… O = 2.610 Å and another with O… O = 2.595 Å. One of the hydrogen atom positions is disordered over two positions with 50% occupancy, which is in agreement with observations on other minerals of the natrochalcite type such as natrochalcite and tsumcorite.

Lotharmeyerite is isotypic (isostructural) to the monoclinic representatives of the tsumcorite group such as tsumcorite and natrochalcite and the other above-mentioned representatives of the lotharmeyerite subgroup.

properties

morphology

In the "Mina Ojuela", Lotharmeyerite develops crusts from isometric microcrystals, mostly only 0.3–0.4 mm in size, sitting on purple adamin and the accompanying matrix. The best known specimen of Lotharmeyerite from the type locality - a 10 × 12 cm plate with countless Lotharmeyerite crystals that form a crust up to 1.5 cm thick - is kept in the collection of Harvard University .

In the "Clara Pit" in the Black Forest, Lotharmeyerite forms kidney-shaped crusts with a concentric radial structure. On material from a find from 1986 in the "Jean Baptiste Mine" near Agios Konstantinos, Lavrion / Greece, "tablets" up to 0.5 mm in size have grown together to form crusts, each tablet consisting of lattice-like twinned crystal aggregates . They represent pseudomorphs based on an unknown precursor mineral.

physical and chemical properties

The crystals of Lotharmeyerite are dark reddish-orange or reddish-flesh-colored, while their streak color is pale orange. The individual spherulites of the concentric spherulitic aggregates from the "Clara Pit" are colored yellow at their edges, while the inside is almost colorless. The surfaces of the translucent crystals have a glass-like sheen , which agrees well with the values ​​for the refraction of light (n = 1.80). Under the microscope , the mineral shows a strong pleochroism in transmitted light from X = Z = light pink orange to Y = dark reddish orange.

No cleavage properties are given for Lotharmeyerite . Due to its brittleness , however , it breaks like amblygonite , with the fracture surfaces being uneven. With a Mohs hardness of ≈ 3, the mineral is one of the medium-hard minerals and, like the reference mineral calcite, can be scratched with a copper coin. The measured density for Lotharmeyerite is 4.2 g / cm³, the calculated density is 4.186 g / cm³. The mineral is neither in the long term nor in the short wavelength UV light , a fluorescent .

Lotharmeyerite is difficult to dissolve in oxalic acid , hydrochloric acid , HCl, and sulfuric acid , H 2 SO 4 .

Education and Locations

Tiny Lotharmeyerite crystals with purple adamin from the Mina Ojuela, Durango, Mexico (step size: 2.7 cm × 2.5 cm × 1.8 cm)

Lotharmeyerit is a typical secondary mineral , which is located in the oxidation zone of arsenic-rich polymetallic non-ferrous metal - deposits formed.

At the type locality "Ojuela Mine" the mineral was found in the form of crusts on a matrix of coarse manganese oxides, which at least partly consist of cryptomelan , brown goethite and colorless to yellow adamin . It also sits on striking purple adamine crystals colored by Mn 3+ , so that Lotharmeyerite represents the most recently formed and youngest mineral phase in the succession.

Paragenesis minerals in the material from the " Clara Mine" are malachite , olivite and quartz , while the Lotharmeyerite in the material from the "Jean Baptiste Mine" is associated with pale greenish, tufted austinite , black chalcophanite and quartz.

As a very rare mineral formation, Lotharmeyerite could only be described from five sites so far (as of 2018). The type locality is the ore chimney "San Judas" of the "Mina Ojuela" near Mapimí, Municipio de Mapimí, State of Durango, Mexico. Lotharmeyerite was later also found in the “Lugaro” (collection area) “La Cigueña” of the same mine.

The second site in the world was the Clara mine in the Rankach valley near Oberwolfach , Black Forest , Baden-Württemberg in Germany . Furthermore, the mineral in the mine "Jean Baptiste" (was modern Greek Ορυχείο Ιωάννου Βαπτιστή, Αγ. Κωνσταντίνος (Καμάριζα) ) at Agios Konstantinos (Kamariza) near Plaka, Mining District Lavrion , Region Attica , Greece found. Lotharmeyerite is also said to have occurred in the "Agoudal Pit" in the cobalt (silver) mining district of Bou Azzer near Taznakht , Ouarzazate Province , Drâa-Tafilalet Region , Morocco , in the form of tabular, tufted, aggregated brown crystals, accompanied by quartz. Finally, during the work that led to the first description of the mineral tapiaite , lotharmeyerite was also extracted from a tunnel in the old, now neglected silver-cobalt mine of the "Mina Jote" in the Pampa Larga mining district near Tierra Amarilla , Copiapó province , Atacama region , Chile , identified.

Occurrences of Lotharmeyerite in Austria or Switzerland are therefore not known.

use

Due to its rarity, Lotharmeyerite is only of interest to mineral collectors.

See also

literature

  • Pete J. Dunn: Lotharmeyerite, a new mineral from Mapimi, Durango, Mexico . In: The Mineralogical Record . tape 14 , no. 1 , 1983, p. 35–36 ( rruff.info [PDF; 157 kB ; accessed on February 20, 2018]).
  • Lotharmeyerite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 66 kB ; accessed on February 20, 2018]). (Attention! - the data contain numerous values ​​for Lotharmeyerite from the "Mina Ojuela", which is actually Manganese Solotharmeyerite)
  • Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p. 802 .

Web links

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

Individual evidence

  1. ↑ a b c d Joël Brugger, Sergey V. Krivovichev, Uwe Kolitsch, Nicolas Meisser, Michael Andrut, Stefan Ansermet, Peter C. Burns: Description and crystal structure of manganlotharmeyerite, Ca (Mn 3+ , ◻, Mg) 2 {AsO 4 , [AsO 2 (OH) 2 ]} 2 (OH, H 2 O) 2 from the Starlera Mn deposit, Swiss Alps, and a redefinition of lotharmeyerite . In: The Canadian Mineralogist . tape 40 , no. 4 , 2002, p. 1597–1608 , doi : 10.2113 / gscanmin.40.6.1597 ( rruff.info [PDF; 1.1 MB ; accessed on February 20, 2018]).
  2. ↑ a b c d e f g h Yongbo W. Yang, Stanley H. Evans, Robert T. Downs, Hexiong Yang: Lotharmeyerite, Ca (Zn, Mn) 2 (AsO 4 ) 2 (H 2 O, OH) 2 . In: Acta Crystallographica . E68, 2012, p. i9 – i10 , doi : 10.1107 / S1600536811054286 ( rruff.info [PDF; 727 kB ; accessed on February 20, 2018]).
  3. ↑ a b Werner Krause, Klaus Belendorff, Heinz-Jürgen Bernhardt, Catherine McCammon, Herta Effenberger, Werner Mikenda: Crystal chemistry of the tsumcorite-group minerals. New data on ferrilotharmeyerite, tsumcorite, thometzekite, mounanaite, helmutwinklerite, and a redefinition of gartrellite . In: European Journal of Mineralogy . tape 10 , no. 2 , 1998, p. 179-206 , doi : 10.1127 / ejm / 10/2/0179 .
  4. ^ A b Anthony R. Kampf, James E. Shigley, George R. Rossman: New data on lotharmeyerite . In: The Mineralogical Record . tape 15 , no. 4 , 1984, pp. 223-226 .
  5. ↑ a b c d e f g h i j k l m n o p q r s t u Pete J. Dunn: Lotharmeyerite, a new mineral from Mapimi, Durango, Mexico . In: The Mineralogical Record . tape 14 , no. 1 , 1983, p. 35–36 ( rruff.info [PDF; 157 kB ; accessed on February 20, 2018]).
  6. ^ Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  485 .
  7. ↑ a b c d Mindat - Lotharmeyerite
  8. ↑ a b c d e Kurt Walenta: Ferrilotharmeyerit from the Clara mine . In: The ore graves . tape 16 , no. 1 , 2002, p. 1-6 .
  9. ↑ a b c d e f Uwe Kolitsch, Branko Rieck, Franz Brandstätter, Fritz Schreiber, Karl Heinz Fabritz, Günter Blaß, Joachim Gröbner: New discoveries from the old mining and the slag from Lavrion (I) . In: Mineral World . tape 25 , no. 1 , 2014, p. 60-75 .
  10. ↑ a b Rudolf Duthaler, Stefan Weiß: Clean, prepare and store minerals. The workbook for the collector . 1st edition. Christian Weise Verlag, Munich 2008, ISBN 978-3-921656-70-9 , p. 173 .
  11. ↑ Lotharmeyerite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 66  kB ; accessed on February 20, 2018]).
  12. ↑ Catalog of Type Mineral Specimens - L. (PDF 70 kB) In: docs.wixstatic.com. Commission on Museums (IMA), December 12, 2018, accessed August 29, 2019 .
  13. ↑ RRUFF - Lotharmeyerite
  14. ^ A b Thomas P. Moore: Fascinating Minerals from the Ojuela Mine, Mapimí, Mexico . In: Lapis . tape 33 , no. 7-8 , 2008, pp. 66-67 .
  15. ^ A b Thomas P. Moore, Peter KM Megaw: Famous mineral localities: The Ojuela Mine, Mapimi, Durango, Mexico . In: The Mineralogical Record . tape 34 , no. 5 , 2003, p. 5-91 .
  16. ↑ Mindat - Number of localities for Lotharmeyerite
  17. ↑ a b List of localities for Lotharmeyerite in the Mineralienatlas and Mindat
  18. ^ Anthony R. Kampf, Stuart J. Mills, Barbara P. Nash, Maurizio Dini, Arturo A. Molina Donoso: Tapiaite, Ca 5 Al 2 (AsO 4 ) 4 (OH) 4 • 12H 2 O, a new mineral from the Jote mine, Tierra Amarilla, Chile . In: Mineralogical Magazine . tape 79 , no. 2 , 2015, p. 345–354 , doi : 10.1180 / minmag.2015.079.2.12 .