Manganese solder armyerite

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Manganese solder armyerite
General and classification
other names
  • IMA 2001-026
  • Mn-Lotharmeyerite
chemical formula Ca (Mn 3+ , □, Mg) 2 {AsO 4 , [AsO 2 (OH) 2 ]} 2 (OH, H 2 O) 2
Mineral class
(and possibly department)
Phosphates, arsenates, vanadates
System no. to Strunz
and to Dana
8.CG.15 ( 8th edition : VII / C.31)
02/40/03/05
Similar minerals Lotharmeyerite, cobalt solderarmeyerite
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  = 9.043  Å ; b  = 6.2314 Å; c  = 7.3889 Å
β  = 116.329 °
Formula units Z  = 2
Frequent crystal faces {001}, {10 1 }, {10 2 }, {110}, {111}
Twinning possibly after [h0l]
Physical Properties
Mohs hardness ≈ 3
Density (g / cm 3 ) 3.77 (measured); 3.75 (calculated)
Cleavage clearly parallel {001}
Break ; Tenacity uneven; brittle
colour brownish red to dark reddish orange
Line color light brown, pale orange to yellow-orange
transparency translucent to translucent
shine Diamond luster
Crystal optics
Refractive indices n α  = 1.785
n β  = 1.814
n γ  = 1.854
Birefringence δ = 0.069
Optical character biaxial positive
Axis angle 2V = 85 ° (measured); 2V = 82 ° (calculated)
Pleochroism strong from X = orange-yellow to Y = red-brown to Z = yellow-orange
Other properties
Chemical behavior sparingly soluble in HCl

Manganese solder 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 (Mn 3+ , □, Mg) 2 {AsO 4 , [AsO 2 (OH) 2 ]} 2 (OH, H 2 O) 2 and is chemically a water-containing calcium - Manganese - magnesium - arsenate with a variable proportion of additional hydroxide ions .

Manganlotharmeyerite develops elongated, plate-like crystals and aggregates up to 1 mm in length at its type locality , which are often fused together subparallel. Clearly transparent, optically homogeneous mineral grains have no crystal faces. The type locality of the mineral is the manganese iron deposit of the "Starlera" mine near Ferrera GR in the Val Ferrera , Hinterrhein , Graubünden , Switzerland , which is located in Triassic platform carbonates .

Etymology and history

Julius Lothar von Meyer - namesake for Lotharmeyerite and the related Manganese Lotharmeyerite

After an unknown mineral was discovered at the end of the 1990s in centimeter to decimeter thick, open fissures in massive Braunite ore of the "Starlera" mine, initial investigations made sure that it was a mineral phase very similar to Lotharmeyerite and thus a new representative of the Tsumcorite group acts. After extensive further research, this new mineral phase was presented to the International Mineralogical Association (IMA), which recognized it in 2001. In 2002, an international team of scientists led by the Swiss-Australian mineralogist Joël Brugger as well as Sergey V. Krivovichev , Uwe Kolitsch , Nicolas Meisser , Michael Andrut , Stefan Ansermet and Peter C. Burns in the Canadian science magazine "The Canadian Mineralogist" identified the mineral as manganese solder armyerite described. The authors named the mineral because of its relationship with Lotharmeyerite and the dominance of trivalent manganese Mn 3+ on the Me (2) position.

The type material for manganese solder armyerite is stored under catalog numbers MGL # 54000 (holotype) and MGL # 54014 (cotype) in the "Collection of the Musée cantonal de géologie de Lausanne" in Lausanne , Switzerland.

Lotharmeyerite crystals from the "Mina Ojuela" near Mapimí , Municipio de Mapimí , Durango , Mexico , which were already described in 1984 by Anthony R. Kampf, James E. Shigley and George R. Rossman, have evolved in the course of the work, which led to the discovery of manganese solder armyerite, also proven to be manganese solder armyerite. Since the manganese soldierite crystals from the "Mina Ojuela" appear in small but clearly formed crystals, most of the morphological results come from the investigation of this material.

classification

The current classification of the International Mineralogical Association (IMA) counts the manganese solderarmyerite to the tsumcorite group with the general formula Me (1) Me (2) 2 (XO 4 ) 2 (OH, H 2 O) 2 , in the 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 Manganlotharmeyerit still Cabalzarit , Cobaltlotharmeyerit , Cobalttsumcorit , Ferrilotharmeyerit , Gartrellit , Helmutwinklerit , Kaliochalcit , Krettnichit , Lotharmeyerit , Lukrahnit , Mawbyit , Mounanait , Natrochalcit , Nickellotharmeyerit , Nickelschneebergit , Nickeltsumcorit , Phosphogartrellit , Rappoldit , Schneebergit , Thometzekit , Tsumcorit , Yancowinnait and Zinc Gartrellite . Manganese solotharmeyerite, together with cabalzarite ( Me (2) = Mg), cobalt solotharmeyerite (Co), ferrilotharmeyerite (Fe 3+ ), lotharmeyerite (Zn) and nickellotharmeyerite (Ni), forms the "Lotharmeyerite subgroup" named after Lotharmeyerite.

In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the manganese solder armyerite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "water-containing phosphates without foreign anions ", where together with cabalzarite, cobalt solder armyerite , cobalt sumcorite , Ferrilotharmeyerite, gartrellite, helmutwinklerite, krettnichite, lotharmeyerite, lukrahnite, mawbyite, mounanaite, nickellotharmeyerite, nickel snow mountainite, phosphogartrellite, rappoldite, snow mountainite, Thometzekit, tsumcorite and zinc gartrellite group the "tsumcorite group" with the "Tsumcellorite" group. VII / C.31 formed.

The 9th edition of Strunz's mineral systematics, which has been in force since 2001 and is used by the International Mineralogical Association (IMA), also assigns manganese solder 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, Cobaltlotharmeyerite, Cobalttsumcorit, Ferrilotharmeyerit, Krettnichit, Lotharmeyerit, Mawbyit, Mounanait, Nickellotharmeyerit, Nickelschneebergit, Schneebergite, Thometzekit and Tsumcorit 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 manganese solder to the class of "phosphates, arsenates and vanadates" and there in the department of "water-containing phosphates, etc.". Here it is in the " Roselith subgroup (monoclinic: P 2 1 / c ) " with system no. 40.02.03 and the other members brandtite , Roselith , Wendwilsonit and Zinkroselith within the subdivision "Water-containing phosphates, etc., with A 2+ (B 2 + ) 2 (XO 4 ) × x (H 2 O)" to be found.

Chemism

Six microprobe analyzes on manganese solderarmyerite resulted in mean values ​​of 0.67% V 2 O 5 ; 53.41% As 2 O 5 ; 3.95% MgO; 16.70% Mn 2 O 3 ; 12.42% CaO; 0.91% Fe 2 O 3 ; 1.07% NiO and 8.84% H 2 O (calculated) as well as smaller amounts (<1% by weight) of Al 2 O 3 , SrO, Na 2 O, CoO and ZnO. Assuming that the tetrahedral positions are fully occupied (As + V = 2), the assumption that for every Me (2) vacancy (vacancy) an [AsO 4 ] 3− group is replaced by an [AsO 2 (OH) 2 ] - -Group is replaced and based on ten oxygen atoms , the empirical formula (Ca 0.94 Sr 0.01 Na 0.01 ) (Mn 3+ 0.450.26 Mg 0.20 Ni 0 , 03 Fe 0.02 Zn 0.02 Al 0.01 Co 0.01 ) 2 (As 0.98 V 0.02 ) 2 O 10 H 4.16 . Based on the crystal structure, this was converted to Ca (Mn 3+ 0.590.24 Mg 2+ 0.17 ) 2 {(AsO 4 ) 0.76 [AsO 2 (OH) 2 ] 0.24 } 2 [ (OH) 0.59 (H 2 O) 0.41 ] 2 and converted to Ca (Mn 3+ , □, Mg) 2 {AsO 4 , [AsO 2 (OH) 2 ]} 2 (OH, H 2 O ) 2 idealized.

The charge equalization mechanism responsible for the incorporation of vacancies on the Me (2) position can be described as follows: { Me 3+ + AsO 4 3− + (OH) - } - → {□ + AsO 2 (OH) 2 - + H 2 O} - . The divalent cations Me (2) are incorporated according to the following coupled substitution : { Me 3+ + (OH) - } - ↔ { Me 2+ + H 2 O} - .

Manganese lotharmeyerite is the Mn 3+ -dominant analogue of the Zn-dominated lotharmeyerite, with which it forms a complete series of mixed crystals . 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

Manganese solder armyerite crystallizes in the monoclinic crystal system in the space group C 2 / m (space group no. 12) with the lattice parameters a  = 9.043  Å ; b  = 6.2314 Å; c  = 7.3889 Å and β = 116.329 ° as well as two formula units per unit cell . Template: room group / 12

The crystal structure of the manganese solder armyerite is identical to the structure of the other representatives of the tsumcorite group. The Me (2) Φ 6 - octahedra (Φ: O 2− , OH - , H 2 O) have common edges and are arranged as chains stretched in the direction of the b-axis [010]. These chains are shared by corners with AsO 4 - tetrahedra linked to each other, thereby forming layers having the composition Me (2) (AsO 4 ) (OH, H 2 O), which are arranged in parallel (001). The topology of this layer is identical to that in natrochalcite, NaCu 2 (SO 4 ) 2 (H 3 O 2 ). The Ca 2+ cations are located between the layers and ensure the connection between the layers in the direction of the a-axis [100].

  • The Me (1) position is coordinated by eight anions. It is completely occupied by Ca
  • The Me (2) position is octahedral coordinated by six ligands and is occupied by Mn 3+ , which also agrees with the Jahn – Teller distortion of the octahedral Me (2) coordination. The refined occupancy of the Me (2) position was determined to be Mn 3+ 0.59 Mg 2+ 0.170.24 .
  • In the minerals of the tsumcorite group, the O (1) position is occupied by OH - or H 2 O groups or both, the O (1) atom being linked to two Me (2) cations. The exclusive occupation of the Me (2) position with trivalent cations means that the O (1) position is completely occupied with hydroxyl groups, whereas the exclusive occupation of the Me (2) position with divalent cations leads to a complete occupation of the O. (1) position with H 2 O molecules leads. The latter also occurs if there are vacancies in the Me (2) position. The occupation of the Me (2) position in the manganese solder armyerite leads to an occupation of the O (1) position with (OH) 0.59 (H2O) 0.41 .
  • AsO 4 3− group : A vacancy in the Me (2) position leads to a lowering of the local symmetry and the replacement of an AsO 4 3− group by an [AsO 2 (OH) 2 ] - group. In the case of manganese solder armyerite, this leads to the replacement of the AsO 4 3− group with {(AsO 4 ) 0.76 [AsO 2 (OH) 2 ] 0.24 } 2.52− .

Manganese 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

Costume and habitus of manganese solder armyerite crystals (same colors represent the same surface shapes)
Manganese solder armyerite crystal drawing 1.png
flat-blade-shaped manganese solder armyerite crystal from the "Mina Ojuela"
Manganlotharmeyerite crystal drawing 2.png
manganese solder armyerite crystal tapering towards [010] and thereby lenticular


In the material from the "Starlera" pit, manganese solder armyerite develops elongated, plate-like, mostly translucent crystals and aggregates up to 1 mm in length, with sub-parallel intergrowths of the crystals often occurring. In contrast, transparent, optically homogeneous mineral grains do not show any crystal faces.

In the “Mina Ojuela”, manganese solder armyerite forms tapering, plate-like, blade-shaped crystals that either sit individually on the matrix as double-sided crystals with a maximum length of 0.2 mm or are loosely fused with one another and thus form aggregates up to 1 mm in size. The mineral is often grown on or into well-formed adamin crystals. The platelets are typically elongated in the direction of the b-axis [010]. In most cases only the basic pinacoid {001} can be identified from them. The broad surface of the platelets is divided approximately longitudinally into two planar shapes, which have a clear curvature both with regard to the b and c axes. If one considers these surface shapes to be parallel to the b-axis, they roughly correspond to the shapes {10 1 } and {20 1 }. On the larger, parallel intergrown crystals, end faces could also be identified which correspond to the surface shapes {111} and {110}. There are signs of twinning along an axis perpendicular to [010], in general terms for twinning along [h0l].

The shape {010} used in the adjacent crystal drawing is, however, fictional and has not been measured goniometrically on the crystals, as they are rounded and taper in the direction of the b-axis. The actually lens-shaped crystals of the "Mina Ojuela" are shown in the other crystal drawing, which was created by adding countless fictitious planar forms.

physical and chemical properties

The crystals of manganese solder armyerite are brown-red to dark reddish-orange, while their streak color is light brown or pale orange to yellow-orange. The surfaces of the translucent to transparent crystals have a diamond-like sheen , which agrees well with the values ​​for light refraction . High values ​​for the refraction of light (n α  = 1.785; n β  = 1.814; n γ  = 1.854) and a very high value for the birefringence (δ = 0.069) were identified on the crystals of the manganese solder armyerite . Under the microscope the mineral shows a strong pleochroism from X = orange-yellow to Y = red-brown to Z = yellow-orange.

Manganese solder armyerite has a clear cleavage parallel {001}, but breaks like amblygonite due to its brittleness , whereby the fracture surfaces are 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 manganese solder armyerite is 3.77 g / cm³, the calculated density is 3.75 g / cm³. There is no information on the mineral's fluorescence in long or short-wave UV light .

Manganese solder is difficult to dissolve in hydrochloric acid , HCl.

Education and Locations

Manganlotharmeyerit is a typical secondary mineral that is not unlike most other representatives of Tsumcoritgruppe in the oxidation zone of arsenic-rich polymetallic non-ferrous metal - deposits , but metamorphosed retrograde , syngeneic - exhalative manganese ores was discovered. Manganese solder armyerite and the associated arsenate minerals are the product of the last stage of arsenic mobilization from the Triassic manganese ores located in limestones and similar carbonate rocks ( carbonate platforms ) during the alpine retrograde metamorphosis . The type locality of manganese solder armyerite is the small Starlera iron-manganese deposit located at an altitude of 2,400 m above sea level near Ferrera in Val Ferrera, Hinterrhein, Graubünden, Switzerland, from which 145 tons of manganese ores were extracted between 1918 and 1920. The ores of Val Ferrera in carbonates have a complex geochemical association with Fe – Mn– (Ba, V, As, Sb, Be, W, REE), which is mainly due to their syngeneic, exhalative formation and their location over a granite-rich continental Basement. Paragenesis minerals of the manganese solder armyerite in the "Starlera" mine are calcite , tilasite and sailaufite .

Interestingly, the mineral was also found in non-ferrous metal deposits. This includes the “Mina Ojuela” in Mexico, where the mineral was found in the form of crusts on a matrix of coarse manganese oxides, which consists of cryptomelane and chalcophanite . Accompanying minerals here are adamin and the manganese-dominant analogue of arseniosiderite , which was also initially thought to be sailaufite, but which is said to be a different mineral.

As a very rare mineral formation, manganese solder armyerite could only be described from three sources so far (status 2018). In addition to the type locality of the “Starlera” mine, these are the “San-Judas” ore chimney of the “Mina Ojuela” near Mapimí, Municipio de Mapimí, State of Durango, Mexico, as well as the “Lugaro” (collecting area) “La Cigueña” of the same mine.

Finally, manganese solder armyerite has also been identified from a tunnel in the old, now negligent silver-cobalt mine of the "Mina Jote" in the Pampa Larga mining district near Tierra Amarilla , Copiapó province , Atacama region , Chile .

There are no known occurrences of manganese solder armyerite in Germany or Austria .

use

Due to its rarity, manganese solder armyerite is only of interest to the mineral collector.

See also

literature

  • 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]).

Web links

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

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 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 Mindat - Manganese solder armyerite
  3. a b c d e f g h i j k l 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 .
  4. 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 .
  5. 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 .
  6. ^ Philippe Roth: Minerals first discovered in Switzerland and minerals named after Swiss individuals . 1st edition. Kristallografik Verlag, Achberg 2007, ISBN 978-3-9807561-8-1 , p. 104-105 .
  7. Mindat - Sailaufit
  8. Mindat - Number of localities for Manganlotharmeyerit
  9. a b List of locations where Manganlotharmeyerit is found in the Mineralienatlas and Mindat
  10. 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 .
  11. Thomas P. Moore: Fascinating Minerals from the Ojuela Mine, Mapimí, Mexico . In: Lapis . tape 33 , no. 7–8 , 2008, pp. 66-67 .