Beudantite

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Beudantite
Beudantite-170099.jpg
Beudantite from the Tsumeb Mine (Tsumcorp Mine), Tsumeb , Oshikoto Region , Namibia (size: 2 cm × 2 cm × 1 cm)
General and classification
other names
  • Bieirosite
  • Beaudantite
  • Dernbachite
chemical formula
  • PbFe 3+ 3 (AsO 4 ) (SO 4 ) (OH) 6
  • PbFe 3 [(OH) 6 | (SO 4 ) | (AsO 4 )]
  • PbFe 3 (As 0.5 S 0.5 O 4 ) (OH) 6
Mineral class
(and possibly department) 		Phosphates , arsenates and vanadates
System no. to Strunz
and to Dana 		8.BL.05 ( 8th edition : VII / B.35)
04/43/01/01
Similar minerals Corkit, Segnitit, Plumbojarosit, Natrojarosit, Jarosite
Crystallographic Data
Crystal system trigonal
Crystal class ; symbol ditrigonal-scalenohedral; 3  2 / m
Space group R 3 m (No. 166)Template: room group / 166
Lattice parameters a  = 7.315  Å ; c  = 17.035 Å
Formula units Z  = 3
Frequent crystal faces {10 1 1}, {0001}, {01 1 2 }
Twinning from biaxial single crystals
Physical Properties
Mohs hardness 3.5 to 4.5
Density (g / cm 3 ) 4.48 (measured); 4.49 (calculated)
Cleavage good after {0001}
Break ; Tenacity clamshell; brittle
colour yellow, greenish yellow, red, dark green, brown, black
Line color gray-yellow to green
transparency transparent to translucent
shine Glass gloss to resin gloss
Crystal optics
Refractive indices n ω  = 1.957
n ε  = 1.943
Birefringence δ = 0.014
Optical character uniaxial negative, often abnormally biaxial
Pleochroism clearly from O = yellow to red-brown to E = colorless to yellow
Other properties
Chemical behavior Completely soluble in hot hydrochloric acid

Beudantite (outdated also Bieirosit and Beaudantit ) is a rather rare mineral from the mineral class of phosphates , arsenates and vanadates with the chemical formula PbFe 3+ 3 (AsO 4 ) (SO 4 ) (OH) 6 . Chemically speaking, beudantite is therefore a lead - iron - arsenate - sulphate with additional hydroxide ions . It crystallizes in the trigonal crystal system and develops isometric (pseudo-cubic or pseudo-octahedral) to tabular crystals up to 5 mm in size, but can also appear in the form of microcrystalline crusts and massive mineral aggregates .

Etymology and history

Name giver for the Beudantite: François Sulpice Beudant

The history of the discovery of the mineral beudantite goes back to the extensive collection of Adolarius Jacob Forster , after whom the mineral forsterite was later named. In 1806, the leading mineral dealer of the 19th century, John Henry Heuland (the mineral heulandite was named after him), inherited this collection from his uncle Jacob Forster. He expanded it considerably and sold it to Charles Hampden Turner in 1820 with the condition that a catalog should be created according to the classification of René-Just Haüy ( Haüyn ). The physician, mineralogist and mathematician Armand Lévy , then living in London, was commissioned to compile this catalog . In the course of this work, Lévy discovered besides some other minerals in 1826 a new lead sulphate containing arsenic and iron, which came from the Luise mine near Horhausen not far from Bürdenbach in the Westerwald. He named it after the French mineralogist François Sulpice Beudant (1787–1850) as Beudantite. Type material for the Beudantite is not defined. The mineral must not be confused with the mineral described by Nicola Covelli (1790–1829) as "Beudantite", which has been shown to be nepheline .

classification

In the outdated, but partly still in use, 8th edition of the mineral classification according to Strunz , the beudantite belonged to the division of "anhydrous phosphates, with foreign anions F, Cl, O, O", where it was used together with corkite , gallobeudantite , hidalgoite , Hinsdalite , kemmlitzite , Orpheit , Schlossmacherite , Svanbergite and Woodhouseit form the Beudantite group VII / B.35 .

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 Beudantite 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 (RO 4 ), so that the mineral can be classified in the sub-section “With medium-sized and large cations; (OH etc.): RO 4  = 3: 1 “is to be found, where the“ Beudantite group ”with the system no. Can be found together with Corkite, Gallobeudantite, Hidalgoit, Hinsdalit, Kemmlitzite, Orpheit, Svanbergite, Weilerite and Woodhouseit. 8.BL.05 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the beudantite to the class of "phosphates, arsenates and vanadates" and there to the category of "composite phosphates etc. (anhydrous composite anions with hydroxyl or halogen)". Here he is the namesake of the "Beudantit group" with the system no. 43.04.01 and the other members Corkite, Hidalgoite, Orpheit, Hinsdalite, Svanbergite, Kemmlitzite, Woodhouseit, Weilerite and Gallobeudantite within the sub-section Compound Phosphates etc., (anhydrous compound anions with hydroxyl or halogen) .

Crystal structure

Beudantite crystallizes in the trigonal crystal system in the space group R 3 m (space group no. 166) , with the lattice parameters a  = 7.315  Å and c  = 17.035 Å and three formula units per unit cell . Template: room group / 166

properties

Costume and habitus of Beudantite crystals
Beudantite 1 pseudocubic.png
pseudocubic crystal from Horhausen, Westerwald
Beudantit 2 pointed rhombohedral.png
pointed rhombohedral crystals from Horhausen, Westerwald
Beudantit tafelig.png
tabular crystal (same colors represent the same surface shapes)

morphology

Beudantite forms crystals with a pseudocubic habit , the main shape of which is the cube-like basic rhombohedron {10 1 1}. By combining it with the basic pinacoid {0001} alone or with a steep rhombohedron or pinacoid , an octahedron that appears to be truncated at a corner is created. Crystals in a pointed rhombohedral habit are created by steep rhombohedra in combination with truncated rhombohedra. In the case of the crystals from the type locality “Luise” pit, the rhombohedral surfaces are occasionally striped horizontally. Furthermore, in tabular crystals according to the basic pinacoid {0001} and - very rarely - also in needle-like crystals. Beudantite can form twins from biaxial single crystals which, exceptionally, simulate a positive uniaxiality in the center.

physical and chemical properties

The color of the crystals and aggregates of the beudantite shows a considerable variation from yellow to greenish-yellow, red, dark green and brown to black. The streak color of the translucent to transparent Beudantite, on the other hand, is gray-yellow to green. The surfaces of the Beudantite crystals have a glass-like to resin-like sheen .

The mineral shows a good cleavage after the basic pinacoid {0001}, but breaks due to its brittleness similar to glass or quartz , whereby the breaking edges are shaped like shell. With a Mohs hardness of 3.5 to 4.5, Beudantite is one of the medium-hard minerals that, like the reference mineral fluorite, can be easily scratched with a pocket knife. The calculated density of the mineral is 4.49 g / cm 3 .

The mineral gives off water in a closed tube, which reddens litmus and gives a white precipitate with barium chloride . Yellow-brown borax pearl in the oxidation flame. By heating with soda and some borax on charcoal with the inner flame, a black pearl is created from which brittle metal particles and a soft lead-like grain can be extracted. When the brittle metal particles are heated in an open tube, typical arsenic odor and white crystalline sublimate . Beudantite is completely soluble in hot HCl; iron and sulfate can be detected in the solution.

Modifications and varieties

Beudantite is the arsenate-dominant analogue of the phosphate-dominated corkite, with which it forms a complete series of mixed crystals. There are also rows of mixed crystals with segnitite and plumbojarosite. Lossenite has proven to be a mixture of scorodite and beudantite.

Education and Locations

Beudantite forms secondarily in the oxidation zone ( iron hat ) of hydrothermal polymetallic, lead-containing ore deposits . Typical accompanying minerals are oliveite , carminite , scorodite , azurite , mimetesite , dussertite , arseniosiderite , pharmacosiderite , bayldonite , fragranceite , anglesite and cerussite occurs.

As a rather rare mineral formation, Beudantite is sometimes abundant at various sites, but overall it is not very widespread. So far (as of 2016) around 420 sites are known.

The type locality of the Beudantite is the “Luise” mine near Bürdenbach in the Altenkirchen district (Westerwald) , Rhineland-Palatinate , but the mineral is also known from the “Schöne Aussicht” mine near Dernbach not far from Montabaur , which is also located in the Westerwald . The main sites in Germany are the Clara mine in the Rankach Valley near Oberwolfach and other locations in the Black Forest (Baden-Württemberg). From Austria from the Wildfrauengrotte, Teschengraben, Krieglach , Fischbacher Alpen , Styria , among others ; from Switzerland, among others, from the northern flank of the Cima della Bianca above the Val Casatscha, Val Cristallina , Graubünden .

The world's best beudantites come from the world-famous Cu-Pb-Zn-Ag-Ge-Cd deposit of the "Tsumeb Mine" (Tsumcorp Mine) in Tsumeb , Oshikoto region , Namibia and from the Corta San Valentín, Sancti Spiritu, Sierra Minera de Cartagena-La Unión, La Unión, Murcia , Spain .

Beudantit is also from Argentina, Australia, Belgium, Chile, China, Eritrea, France, Greece, Greenland, Iran, Ireland, Italy, Japan, Canada, Kazakhstan, Cuba, Mexico, Morocco, Netherlands, Norway, Peru, Portugal, Russia, Zambia, South Africa, Czech Republic, Hungary, the United Kingdom and the United States are known.

use

Beudantite is of little economic importance. In ores in the oxidation zone of sulphide deposits ( Iron Hat ), beudantite is the main carrier of silver and is mined in some deposits. In addition to lead and arsenic , the minerals of the jarosite and beudantite group can contain other highly toxic heavy metals (e.g. thallium ) and are almost insoluble in water. They therefore play an important role in the fixation of heavy metals from industrial waste and dumps and can prevent heavy metals from being flushed into the groundwater.

See also

literature

  • Beudantite . 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 May 2, 2020]).
  • John L. Jambor: Nomenclature of the Alunite Supergroup . In: Canadian Mineralogist . tape 37 , 1999, pp. 1323–1341 ( rruff.info [PDF; 1.8 MB ; accessed on May 2, 2020]).
  • Keith M. Scott: Nomenclature of the Alunite Supergroup: Discussion . Canadian Mineralogist, 2000, p. 1295–1297 ( rruff.info [PDF; 688 kB ; accessed on May 2, 2020]).
  • P. Leverett, AR McKinnon, PA Williams: Supergene geochemistry of the Endeavor ore body, Cobar, NSW, and relationships to other deposits in the Cobar Basin . In: Proceedings of the CRC LEME Regional Regolith Symposia 2005 . 2005, p. 191–194 ( crcleme.org.au [PDF; 97 kB ; accessed on May 2, 2020]).

Web links

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

Individual evidence

  1. ↑ a b c d e f g h Beudantite . 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 May 2, 2020]).
  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.  462 (English).
  3. ↑ a b Peter Bayliss, Uwe Kolitsch, Ernest H. Nickel, Allan Pring: Alunite supergroup: recommended nomenclature . In: Mineralogical Magazine . tape 74 , 2010, pp. 919–927 (English, rruff.info [PDF; 216 kB ; accessed on May 2, 2020]).
  4. ↑ a b Jan T. Szymanski: The Crystal Structure of Beudantite, Pb (Fe, Al) 3 [(As, S) O 4 ] 2 (OH) 6 . In: Canadian Mineralogist . tape 26 , 1988, pp. 923-932 ( rruff.info [PDF; 1.1 MB ; accessed on May 2, 2020]).
  5. ^ Armand Lévy : Description of two new minerals (Queen, Beudantite) . In: Annals of Philosophy . tape  11 . Baldwin, Cradock & Joy, London 1826, pp. 194–196 ( limited preview in Google Book search).
  6. ↑ Lévy, Armand (1795-1841). In: mineralogicalrecord.com. Curtis Schuh's Bio-Bibliography of Mineralogy, accessed May 2, 2020 .
  7. ↑ a b c Carl Hintze : Handbook of Mineralogy. First volume. Fourth section. 2nd half . 1st edition. Veit & Co., Leipzig 1933, p.  724-729 .
  8. ↑ Beudantite. In: mindat.org. Hudson Institute of Mineralogy, accessed May 2, 2020 .
  9. ↑ Localities for Beudantite. In: mindat.org. Hudson Institute of Mineralogy, accessed May 2, 2020 .
  10. ↑ Find location list for Beudantite in the Mineralienatlas and Mindat , accessed on May 2, 2020.
  11. ^ A. Roca, J. Viñals, M. Arranz, J. Calero: Characterization and alkaline decomposition / cyanidation of beudantite-jarosite materials from Rio Tinto gossan ores . In: Canadian Metallurgical Quarterly . tape 36 , 1999, pp. 93-103 , doi : 10.1016 / S0008-4433 (99) 00003-8 (English).
  12. ↑ L. Sánchez, M. Cruells, A. Roca: Sulphidization-cyanidation of jarosite species: Applicability to the gossan ores of Rio Tinto . In: Hydrometallurgy . tape 42 , 1996, pp. 35-49 , doi : 10.1016 / 0304-386X (95) 00076-S (English).
  13. ^ U. Kolitsch, A. Pring: Crystal chemistry of the crandallite, beudantite and alunite groups: a review and evaluation of the suitability as storage materials for toxic metals . In: Journal of Mineralogical and Petrological Sciences . tape 96 , 2001, p. 67–78 ( jstage.jst.go.jp [PDF; 549 kB ; accessed on May 2, 2020]).
  14. ↑ Christophe Roussel, Catherine Néel, Hubert Bril: Minerals controlling arsenic and lead solubility in an abandoned gold mine tailings . In: Science of the total environment . tape 263 , 2000, pp. 209-219 , doi : 10.1016 / S0048-9697 (00) 00707-5 (English).
  15. ↑ MX Zheng, JM Xu, L. Smith, R. Naidu: Why a fern (Pteris multifida) dominantly growing on an arsenictheavy metal contamînated soil does not accumulate arsenic? In: Journal de Physique IV France . tape 107 , 2003, p. 1409 , doi : 10.1051 / jp4: 20020566 .