Bismuthite
| Bismuthite | |
|---|---|
 |
|
| General and classification | |
| other names |
Bismuth spar |
| chemical formula |
|
|
Mineral class (and possibly department) |
Carbonates and nitrates |
|
System no. to Strunz and to Dana |
5.BE.25 ( 8th edition : V / C.09) 16a.03.05.01 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-pyramidal; mm 2 |
| Space group | Imm 2 (No. 44) |
| Lattice parameters | a = 3.865 Å ; b = 3.862 Å; c = 13.675 Å |
| Formula units | Z = 2 |
| Physical Properties | |
| Mohs hardness | 2.5 to 3.5 |
| Density (g / cm 3 ) | measured: 6.1 to 7.7; calculated: 8.25 |
| Cleavage | clearly to well after {001} |
| colour | straw to brownish yellow, light yellow, light green, greenish gray, blue, brown, black |
| Line color | gray-white |
| transparency | translucent to opaque |
| shine | Glass gloss to wax gloss, pearlescent, matt |
| Crystal optics | |
| Refractive indices |
n α = 2.120 to 2.150 n β = 2.120 to 2.300 n γ = 2.28 |
| Birefringence | δ = 0.120 to 0.160 |
Bismutite , not to be confused with the bismuth sulfide Bismuthinite , outdated also known as bismuth spar , is a rarely occurring mineral from the mineral class of "carbonates and nitrates" with the chemical composition Bi 2 [O 2 | CO 3 ] and is therefore chemically one bismuth - carbonate with additional oxygen ions .
Bismutite crystallizes in the orthorhombic crystal system and develops predominantly spherical, radial-radial or massive to powdery mineral aggregates of mostly white, gray or yellow color. Green, blue, brown and black colored bismutites have also been found.
Etymology and history
Bismutite was found for the first time in the “Poor aid pit” near Ullersreuth ( Hirschberg (Saale) , Thuringia). The first description of the mineral is August Breithaupt's publication from 1841. However, Breithaupt mentioned that carbonic bismuth oxide had already been found several times before, although this was present in a mixture and could not be precisely characterized:
“It has already been stated several times that a carbonic acid bismuth oxide occurs in nature, but no characteristic can be found in any mineralogy. Finally, Mr. Gregory said that at St. Agnes in Cornwall, carbonic bismuth was found. However, his examination proves that he dismantled a muddled body. [...] On the iron stone mine "Arme Hülfe zu Ullersreuth" near Hirschberg in the Reussian Voigtlande is found, among other things, in a horny, dense brown iron ore: solid bismuth, bismuth luster and hypochlorite, the former in sprinkled or small parts, the second in ingrown needle-shaped crystals and also coarse crystals. These two metallic minerals, accompanied by copper pebbles, are sometimes at their edges and on the surface, more usually, however, transformed through and through into a pale gray or green substance which, I have found, consists more or less purely of carbonic acid bismuth, and which, since it is a peculiar natural product in any case, may bear the name: bismuthite. "
Breithaupt named the mineral based on the high bismuth content of over 80%.
classification
In the outdated, but still in use 8th edition of the mineral classification according to Strunz , the bismuthite belonged to the common mineral class of "carbonates, nitrates and borates" and there to the department "anhydrous carbonates with foreign anions ", where together with phosgenite it forms the "phosgenite bismuthite -Group "with the system no. V / C.09 and the other members Beyerite and Kettnerite .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns bismuthite to the newly defined class of "carbonates and nitrates" (the borates form a separate class here), but also in the department of “carbonates with additional anions; without H 2 O “. However, this is further subdivided according to the predominant metals in the compound, so that the mineral can be found according to its composition in the sub-section "With Pb, Bi", where it is the only member of the unnamed group 5.BE.25 .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns bismuthite, like the outdated Strunz system, to the common class of “carbonates, nitrates and borates” and there to the “carbonates - hydroxyl or halogen” class. Here he is the only member of the unnamed group 16a.03.05 within the subsection “Carbonates - Hydroxyl or Halogen with (AB) 2 (XO) 3 Z q ”.
Crystal structure
According to initial structural measurements, bismuthite appeared to crystallize in tetragonal symmetry. However, with this assumption, the structure could not be completely solved. A new structural analysis in 2002 finally showed that bismuthite crystallizes in the orthorhombic crystal system in the space group Imm 2 (space group no.44 ) with the lattice parameters a = 3.865 Å , b = 3.862 Å and c = 13.675 Å as well as two formula units per unit cell , the unit cell, however, shows a pronounced pseudotetragonal arrangement.
Education and Locations
Bismutite is formed as a secondary mineral through weathering (mostly oxidation) from other bismuth minerals or native bismuth. It therefore occurs in paragenesis with native bismuth , bismuthinite , bismuth ferrite , chalcopyrite and goethite .
As a rather rare mineral formation, bismuthite can sometimes be abundantly abundant at various sites, but overall it is not very common. So far (as of 2017) around 700 sites are known. In addition to its type locality Ullersreuth in Thuringia , bismuthite was found in Germany, among other places, in Baden-Württemberg (Black Forest), Bavaria (Fichtelgebirge, Spessart), Hesse (Odenwald), Lower Saxony (Harz), North Rhine-Westphalia (Sauerland, Siegerland), Rhineland- Palatinate (Siegerland, Westerwald), Saxony-Anhalt (Harz) and Saxony (Ore Mountains).
In Austria, the Minera appeared at the Hüttenberger Erzberg and near the Duisburger Hütte in Carinthia, at Kottaun (municipality of Geras ) in Lower Austria, at several locations in the Salzburg region and at Brunngraben near Flatschach and Sankt Oswald in Freiland in Styria.
In Switzerland, bismuthite has so far been found mainly in the cantons of Graubünden and Valais .
Other locations include Argentina, Armenia, Ethiopia, Australia, Bolivia, Brazil, Chile, China, Finland, France, Greece, India, Italy, Japan, Canada, Kazakhstan, the Democratic Republic of the Congo, Madagascar, Mexico, Mongolia, Mozambique , Namibia, Norway, Papua New Guinea, Peru, Poland, Portugal, Rwanda, Romania, Russia, Sweden, Zimbabwe, Slovakia, Spain, South Africa, Tajikistan, Czech Republic, Hungary, the United Kingdom (UK) and the United States of America (UNITED STATES).
See also
literature
- A. Breithaupt: XV. About the natural carbonic acid bismuth oxide . In: Annals of Physics and Chemistry . tape 23 , 1841, pp. 627–630 ( rruff.info [PDF; 476 kB ; accessed on January 17, 2017]).
- Clifford Frondel : Mineralogy of the oxides and carbonates of bismuth . In: American Mineralogist . tape 28 , 1943, pp. 521-535 ( rruff.info [PDF; 979 kB ; accessed on January 17, 2017]).
- 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. 715 .
- Petr Korbel, Milan Novák: Mineral Encyclopedia (= Villager Nature ). Nebel Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 126 .
Web links
- Mineral Atlas: Bismutite
- RRUFF Database-of-Raman-spectroscopy - Bismutite (English)
- American Mineralogist Crystal Structure Database - Bismutite (English)
- Thomas Witzke : The discovery of bismuth at www.strahl.org
Individual evidence
- ↑ Hans Lüschen: The names of the stones. The mineral kingdom in the mirror of language . 2nd Edition. Ott Verlag, Thun 1979, ISBN 3-7225-6265-1 , p. 188, 344 .
- ↑ a b c d Joel D. Grice: A solution to the crystal structures of bismutite and beyerite . In: The Canadian Mineralogist . tape 40 , 2002, p. 693–698 ( rruff.info [PDF; 650 kB ; accessed on January 17, 2017]).
- ^ 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. 300 .
- ↑ a b c Webmineral - Bismutite (English)
- ↑ a b bismutites . 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; 63 kB ]).
- ↑ a b c d Mindat - Bisutite (English)
- ↑ a b A. Breithaupt: XV. About the natural carbonic acid bismuth oxide . In: Annals of Physics and Chemistry . tape 23 , 1841, pp. 627–630 ( rruff.info [PDF; 476 kB ; accessed on January 17, 2017]).
- ↑ Find location list for bismutite in the Mineralienatlas and Mindat