Puff cornite

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Puff cornite
Hauchecornite-135221.jpg
Hauchecornite crystal from the "Friedrich" pit near Wissen in Siegerland, Rhineland-Palatinate, Germany (field of view: 3 mm)
General and classification
other names

IMA 1975-006a

chemical formula
  • Ni 9 BiSbS 8
  • Ni 9 Bi (Sb, Bi) S 8
  • Sb (NiBi) Ni 8 S 8
Mineral class
(and possibly department)
Sulfides and sulfosalts
System no. to Strunz
and to Dana
2.BB.10 ( 8th edition : II / B.15)
04/03/02/02
Similar minerals Pyrrhotite, arsenic horny cornite, bismuth horny cornite, telluric horny cornite, Tučekit
Crystallographic Data
Crystal system tetragonal
Crystal class ; symbol ditetragonal-dipyramidal; 4 / m  2 / m  2 / m
Space group P 4 / mmm (No. 123)Template: room group / 123
Lattice parameters a  = 7.300  Å ; c  = 5.402 Å
Formula units Z  = 1
Frequent crystal faces {001}, {100}, {110}, {101}, {112}, {11l}, vicinal areas
Physical Properties
Mohs hardness 5; Vickers hardness VHN 50g = 447-655 kg / mm²
Density (g / cm 3 ) 6.35-6.47 (measured); 6.58 (calculated)
Cleavage no
Break ; Tenacity flat mussel; ????
colour light yellow to pale bronze yellow, tapering to dark
Line color grey black
transparency opaque
shine lively metallic shine on freshly broken surfaces
Other properties
Chemical behavior attacked by HCl, soluble in HNO 3 , easily soluble in aqua regia

Hauchecornite is a very rarely occurring mineral from the mineral class of " sulfides and sulfosalts " with the chemical formula Ni 9 BiSbS 8 . From a chemical point of view, the mineral is therefore an antimony - nickel - bismuth - sulfide . Hauchecornite crystallizes in the tetragonal crystal system and develops up to 2 cm large, {001} tabular as well as short prismatic, pseudo-cubic and pseudo-octahedral crystals .

Etymology and history

The Hauchecornit was named after him: Wilhelm Hauchecorne (1824–1900)

In 1884 an ore nest was found on the Friedrich mine near Niederhövels in the Hamm mining district in the spatheisen ore medium of a hanging strand separated from the main corridor, which was weakly attached to the hanging wall of the medium at about the height of the Erbstollnsole, and about 2½ m in length, downwards expanding to almost 0.75 m, extending almost 5 m deep into the Spatheisenstein . In its upper part, this mainly contains millerite and hauchecornite. The latter was found here for the first time in the world - the Friedrich pit is the first place where the hauchecornite was found. The Prussian government geologist Robert Scheibe had this mineral as early as August 1888 at the general assembly of the German Geological Society in Halle a./S. A comprehensive description as a new mineral could not be given until 1893 due to difficulties in chemical analysis. Disk named the mineral after the geologist Heinrich Lambert Wilhelm Hauchecorne (1828–1900), Secret Oberbergrath and director of the Royal Geological State Institute and Mining Academy in Berlin . Hauchecorne was u. a. responsible for the coordination of the geological survey in all Prussian provinces and the creation of geological maps. The color and display style he chose became a model for map design beyond the borders of the German Reich.

Although the work of Robert Scheibe represented an exemplary, detailed description of the breath cornite, with a complete characterization of the goniometric, physical and chemical information as well as a careful investigation of socialization and paragenesis, the breath cornite slipped further and further into the group of minerals in question and was soon considered to be until 1950, as a mixture of several different minerals. As recently as 1944, a passage in the 7th edition of “Dana's System System of Mineralogy” reads: “The original elaborate description needs revision.” Only confirmed after another intensive examination by Martin Peacock , who corrected the chemical composition and improved the crystallographic data the independence of Hauchecornit as a mineral. In 1980 the Hauchecornite was redefined as Ni 9 BiSbS 8 and a group of minerals named after this sulfo salt was established.

The type material of the mineral is stored at Harvard University , Cambridge , Massachusetts , USA , under catalog number 89710.

classification

In the meantime outdated, but still in use 8th edition of the mineral classification by Strunz of Hauchecornit belonged to the mineral class of "sulfides and sulfosalts" and there to the general ward of the "thio" where he along with Arsenhauchecornit , Bismutohauchecornit , Tellurohauchecornit and Tučekit the Hauchercornit- Group with the system no. II / B.15 .

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 Hauchecornite to the class of "sulfides and sulfosalts" and there in the department of "metal sulfides, M: S> 1: 1 (mainly 2: 1) ”. However, this division is further subdivided according to the predominant metals in the compound, so that the mineral is classified in sub-division “B. mit Nickel (Ni) ”is to be found, where it also forms the unnamed group 2.BB.10 together with arsenic breath cornite, bismuth breath cornite, tellurium breath cornite and Tučekit .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , sorts the hauchecornite into the class of "sulfides and sulfosalts" and there into the department of "sulfosalts". Here it is within the subsection “ Sulphosalts with the ratio z / y = 4 and the composition (A + ) i (A 2+ ) j [B y C z ], A = metals, B = semi-metals, C = non-metals " find, where together with bismuth whiff cornite, tellurous whiff cornite, arsenic whiff cornite and tučekit the "whiff cornite group" with the system no. 02/03/05 forms.

Crystal structure

Hauchecornite crystallizes in the tetragonal crystal system in the space group P 4 / mmm (space group no. 123) with the lattice parameters a  = 7.300  Å and c  = 5.402 Å and β = 117.1 ° as well as one formula unit per unit cell . Template: room group / 123

In the crystal structure of the hauchecornite , square NiS 4 planes (planes) are connected via common corners and edges in such a way that a three-dimensional network is created, which is formed by bonds to six-coordinate Bi [6] and eight-coordinate Sb [8] atoms is reinforced. The structure contains 19 atoms on 6 non-equivalent types of positions: one Ni (1) [6] atom, eight Ni (2) [5] atoms, one Bi [6] atom, one M [8] - Atom, four S (1) [5] and four S (2) [5] atoms. It can also be described in such a way that double Ni (2) -S ribbons are connected by Bi-Ni (1) chains in parallel [001]. The M positions (0.75Sb + 0.3Bi) are on the intersection of the four double bands. Bi and Ni (1) are octahedral coordinated. Ni (2) is in a distorted square-planar coordination with 4S. The M position is surrounded by eight Ni (2) atoms. The closest Ni-Ni distances in the double bands suggest an orbital interaction.

Hauchecornit group

In 1972, three varieties of hauch cornite were described, an antimony dominant from the Friedrich Mine at Wissen and an arsenic dominant variety from the Vermilion Mine and a tellurium dominant variety from the Strathcona Mine, both in the area of ​​the Sudbury nickel deposit, Ontario, Canada. The arsenic and tellurium-dominant “varieties” were renamed a little later to arsenic cornite and tellurium cornite and have been considered new minerals ever since. In 1980 the hauchecornite group was established with a general formula (Ni, Co, Fe) 9 Bi M S 8 , where Bi and M stand for As, Sb, Bi and Te in two non-equivalent structural positions. The classification of the representatives of the hauchecornite group is based on the dominance of the elements on the Bi- and M-positions, whereby it is assumed that nickel is dominant on the Ni (1) and Ni (2) -positions and sulfur is dominant on the S (1 ) and S (2) positions. In Hauchecornit sensu stricto, Ni is dominant on the Ni (1) and Ni (2) position, Bi dominant on the Bi position, Sb dominant on the M position and S dominant on the S (1) and S ( 2) position. Tučekit, Ni 9 Sb 2 S 8 , is the antimony dominant analog of the hauchecornite. Bismuth puff cornite, Ni 9 Bi 2 S 8 , is the bismuth-dominant analogue of puff cornite.

properties

morphology

Larger Hauchecornit crystal from the type locality Grube Friedrich near Wissen, built from smaller individuals that are not completely parallel

At the type locality, the crystals of the hauched cornite reach maximum sizes of 10 mm × 10 mm × 6 mm, but are usually much smaller. For tabular crystals grown in chalcopyrite from the vermilion mine, maximum dimensions of 2 mm × 20 mm are given. It was already established in the type publication that larger crystals are usually much less fully developed than small ones. It is usually easy to see that such larger individuals are made up of not completely parallel, smaller crystals and that this often results in a curvature of the surfaces, especially of the prism and base pinacoid, and, if the sub-individuals are unequal in height, the base pinacoid is tiled. This is illustrated by the illustration from the original work by R. Scheibe.

Hauchecornite crystals from the Friedrich pit can be divided into four different types due to their formation in terms of crystal costume and crystal habit , namely pseudo-octahedral, short prismatic, cubic and {001} thick or thin tabular crystals - which can also be seen in the crystal drawings on the right. In the original publication of the Hauchecornit, R. Scheibe presented these different types in detail and also pointed out that in addition to the five "pure" forms, there are also mixed forms between the habitus varieties mentioned.

  • The tabular habitus is the one most frequently observed on the crystals of the type locality. Thin-tabular crystals have little area and show the basic pinaciod {001} as the supporting crystal form, to which the prism {110} and the dipyramid {112} are added. In the case of larger-area crystals, the two dipyramids {101} and {112} can also be identified.
  • With thick tabular crystals {110}, {001} and {112} are the dominant surface forms; they are also more or less in balance. In the case of significantly more extensive crystals, the prism {100} as well as {101} and {111} can also be added.
  • Short prismatic crystals are relatively rare. They are stretched along the c-axis [001] and are therefore pseudo-cube-shaped. The supporting form is the prism {110}, plus the basic pinacoid {001} and pyramid {111}. {100}, {101} and {112} are only of subordinate design.
  • In the simplest case, pseudo-cubic crystals show combinations of the equilibrium surface forms {110} and {001}. The crystals resemble simple cubes. Usually, however, {112} is found alone or together with {111} in the crystal costume. More rarely, {101} and {100} were also observed on the pseudo-cubic crystals.
  • The least common are pseudo-octahedral crystals with the dominant dipyramid {111} as the supporting shape. The costume is completed by the surfaces of the basic pinacoid {001}.

Crystals from the "Friedrich" pit are also characterized by characteristic stripes on the crystal surfaces. Due to the different direction of the stripes on the prism {110}, two different types can be distinguished.

In the case of crystals of the first type, this stripe runs horizontally (parallel [010]). It is usually strong and arises from an alternating combination of {110} and {112}, or of {110} and {111}, or also of very steep, to {110} vicinal octahedra I. position. In the case of crystals of the second type, the stripes on {110} run perpendicular (parallel [001]). It is usually very delicate that it cannot be seen which surface it creates in combination with {110}. The striations occurring on the other surfaces are the same for both types. The surfaces of {100} are finely striped vertically. On the surfaces of the dipyramids (111) and {112} the stripes run parallel to the combination edge with the prism (110). The surfaces of the dipyramid {101} are horizontally striped. The stripes, which are not equally strong on all surfaces, can occasionally be completely absent on individual surfaces. On the prisms {110} and {100} it is sometimes so delicate that these flat shapes appear smooth to the naked eye.

Physical Properties

The crystals of the touch cornite are light yellow to pale bronze yellow in color, but darken relatively quickly. The streak color of the mineral is described as gray-black. The opaque crystals have a lively metallic sheen on fresh fractured surfaces . The mineral shows no discernible cleavage , but breaks like quartz , with the fracture surfaces being flat-shelled. With a Mohs hardness of 5, hauchecornite is one of the medium-hard minerals that, like the reference mineral apatite, can just be scratched with a pocket knife. The measured density is between 6.35 and 6.47 g / cm³ depending on the author; the calculated density is 6.58 g / cm³.

In the reflected light (bevel), the touch of cornite is light bronze-yellow (in air, significantly reduced in oil). Against Millerite there is a decided tinge of brown-pink with a slightly lower reflectivity than Millerite. Similar in oil, but with a slightly olive-colored cast. The reflectivity is high at 47.7 to 50.6%. Reflective pleochroism is weak and barely visible in air, and much higher in oil. The anisotropy effects are clear for crossed polars in air and oil, but the colors are not conspicuous.

Chemical properties

The mineral is attacked by air-free hydrochloric acid with the development of hydrogen sulfide H 2 S. It dissolves with separation of sulfur in nitric acid (HNO 3 ), and also slightly in aqua regia (aqua regia). The solution looks green and, when diluted with plenty of water, gives the familiar cloudiness due to the precipitation of basic bismuth compounds. In front of the soldering tube on charcoal, the whiff of cornite melts slightly to a light bronze-yellow, magnetic ball and gives a dark yellow coating that becomes lighter when it cools. Melted with soda on charcoal, he gives hepar and a brittle magnetic metal grain. He colors the borax pearl purple in the oxidizing fire. When it cools, it turns red-brown. In the reducing flame the pearl becomes cloudy.

Education and Locations

Hauchecornite is formed by hydrothermal processes in nickel - and antimony - containing ore veins during the decomposition of the primary nickel ores ullmannite and gersdorffite . At the type locality it comes in paragenesis mainly with millerite, but also bismuth-arsenic-containing ullmannite (kallilite), antimony-containing gersdorffite, siegenite , bismuthhinite , solid gold , galena and sphalerite as well as the veins quartz and siderite and the decomposition products "nickel vitriol" “, Erythrin and Goethite . In the Canadian deposits is as an accessory mineral mainly chalcopyrite to mention next is the ore from Hauchecornit leading Millerit, pyrrhotite , Gersdorffit, pyrite , gold, Nickelin , galena, native copper , Sperrylith , Michenerit and Froodit .

Hauchecornite has only been described as a very rare mineral formation from a few localities. So far (as of 2016) around 30 sites are known. As type locality , the pit "Friedrich" in the true Wissen district Schönstein in Siegerland , Rhineland-Palatinate .

Other sites in the Siegerland are the "Neue Eintracht" pit near Freusburg and the "Grüneau" pit near Schutzbach , both not far from Betzdorf , Rhineland-Palatinate , as well as the " Brethrenbund pit " in the Kohlenbachtal near Eiserfeld , the " Eisernhardter Tiefbau " pit near Eisern , the Stahlberg mine in the Hilchenbach district of Müsen , the “ Stahlseifen ” mine near Salchendorf not far from Neunkirchen , the “Jakobskrone” mine in the Siegen district of Achenbach and the “Silberquelle” mine near Obersdorf near Wilnsdorf not far from Siegen, all in North Rhine-Westphalia . Finally also from the Niederschlema-Alberoda deposit area in Saxony .

Find places in Europe are "Gödölye-bérc", Fertőrákos in the Balfi Mountains, Győr-Moson-Sopron County , Hungary ; the lead-zinc-silver deposits of the "Miniera Nieddoris" and the "Miniera Montevecchio", both near Arbus , Province of Sud Sardegna , Sardinia , Italy ; the “ Montschegorsk ” copper-nickel deposit in Monche Tundra, Kola Peninsula , Murmansk Oblast , Northwestern Federal District , Russia ; the copper-silver-gold deposit " Rudňany " (formerly Kotterbach), Okres Spišská Nová Ves , Košický kraj , Slovakia ; and the “Tunaberg” copper-cobalt ore field near the town of the same name, Nyköping , Södermanland County , Sweden . Locations for hauchecornite in Austria and Switzerland are unknown.

From the deposit "Xingshutai" District Yanqing of centrally-administered city of Beijing in northern China ; the Ag-Pb deposit of the "Central Balstrup Mine" in the Zeehan ore field, Local Government Area West Coast Municipality , Tasmania , Australia ; as well as the "Joculluni Mine" and the "Marimarini Mine", both in the Berenguela district, Pacajes province , La Paz department , both in Bolivia .

Finally, from a number of Canadian deposits and sites such as the Easter Island Dike on Great Slave Lake , Northwest Territories ; and the "Vermilion Mine", Denison Township ; the "McCreedy East Mine", the "McCreedy West Mine" (Levack West Mine), Levack Township and the "Strathcona Mine", all Levack Township; the "Maclennan Mine" and the "Victor Deep Mine", both MacLennan Township ; and Norman Property, Norman Township , all in the Sudbury District , all in Ontario .

use

Due to their rarity, specimens with whiff of cornite crystals are primarily sought-after formations for collectors.

See also

literature

  • Hauchecornite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF, 62 kB )
  • Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 424 (first edition: 1891).
  • 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. 303 .
  • Paul Ramdohr : The ore minerals and their adhesions . 4th edition. Akademie-Verlag, Berlin 1975, p. 437-438 .

Web links

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

Individual evidence

  1. a b IMA / CNMNC List of Mineral Names; May 2016 (PDF, 1.6 MB)
  2. a b c d e f g h i j k l m Hauchecornite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF, 62 kB )
  3. ^ A b Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagsbuchhandlung Nägele u. Obermiller, Stuttgart 2001, ISBN 3-510-65188-X , p.  68-69 .
  4. a b c d e Paul Ramdohr : The ore minerals and their adhesions . 4th edition. Akademie-Verlag, Berlin 1975, p.  437-438 .
  5. a b c Bernhard Pracejus: The ore minerals under the microscope, An optical guide . 2nd Edition. Elsevier, Amsterdam 2015, ISBN 978-0-444-62725-4 , pp. 242-243 .
  6. ^ Robert Scheibe: Minutes of the meeting of August 15, 1888 . In: Journal of the German Geological Society . tape 40 , 1888, pp. 610–618 ( rruff.info [PDF; 503 kB ]).
  7. a b c d e f Robert Scheibe: Ueber Hauchecornit, a nickel bismuth sulfide from the Friedrich mine (mining district Hamm ad Sieg) . In: Yearbook of the Royal Prussian Geological State Institute and Bergakademie zu Berlin for the year 1891 . tape XII , 1893, p. 91–125 ( rruff.info [PDF; 2.7 MB ]).
  8. ^ Charles Palache , Harry Berman , Clifford Frondel : The system of mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892: Volume I Element, Sulfides, Sulfosalts, Oxides . 7th edition. John Wiley & Sons, New York 1944, pp.  242 .
  9. ^ Martin Alfred Peacock : Hauchecornite . In: American Mineralogist . tape  35 , 1950, pp. 440–446 ( rruff.info [PDF; 451 kB ]).
  10. a b c J. Just : Bismuth hauchecornite - new name: hauchecornite redefined . In: Mineralogical Magazine . tape 43 , 1980, pp. 873–876 ( rruff.info [PDF; 261 kB ]).
  11. ^ V. Kocman, EW Nuffield: The crystal structure of antimonian hauchecornite from Westphalia . In: The Canadian Mineralogist . tape 12 , 1974, p. 269–274 ( rruff.info [PDF; 480 kB ]).
  12. a b c RI Gait, DC Harris: Hauchecornite - antimonian, arsenian and tellurian varieties . In: The Canadian Mineralogist . tape 11 , 1972, p. 819–825 ( rruff.info [PDF; 353 kB ]).
  13. ^ RI Gait, DC Harris: Arsenohauchecornite and tellurohauchecornite: new minerals in the hauchecornite group . In: Mineralogical Magazine . tape 43 , 1980, pp. 877-878 ( rruff.info [PDF; 98 kB ]).
  14. J. Just: Tučekite, a new antimony analogue of hauchecornite . In: Mineralogical Magazine . tape 42 , 1978, pp. 278 , doi : 10.1180 / minmag.1978.042.322.18 ( rruff.info [PDF; 54 kB ]).
  15. Mindat - Number of localities for Hauchecornit
  16. a b List of localities for hauchecornite in the Mineralienatlas and Mindat
  17. Axel Hiller, Werner Schuppan: Geology and Uranium Mining in the Schlema-Alberoda Revier (Mining in Saxony, Mining Monograph Volume 14) . 1st edition. Saxon State Office for Environment, Agriculture and Geology, Dresden 2008, ISBN 978-3-9811421-3-6 , p. Appendix 5 .