Jarosite
| Jarosite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | KFe 3 3+ [(OH) 6 | (SO 4 ) 2 ] |
|
Mineral class (and possibly department) |
Sulfates (and relatives, see classification ) |
|
System no. to Strunz and to Dana |
7.BC.10 ( 8th edition : VI / B.11) 02/30/05/01 |
| Similar minerals | Limonite |
| Crystallographic Data | |
| Crystal system | trigonal |
| Crystal class ; symbol | trigonal-pyramidal; 3 |
| Room group (no.) | R 3 m (No. 166) |
| Lattice parameters | a = 7.30 Å ; c = 17.27 Å |
| Formula units | Z = 3 |
| Physical Properties | |
| Mohs hardness | 2.5 to 3.5 |
| Density (g / cm 3 ) | measured: 2.91 to 3.26; calculated: 3.127 |
| Cleavage | clearly after {0001} |
| Break ; Tenacity | shell-like to uneven |
| colour | brown, yellow |
| Line color | light yellow |
| transparency | transparent to translucent |
| shine | Diamond to glass gloss, matt |
| Crystal optics | |
| Refractive indices |
n ω = 1.815 to 1.820 n ε = 1.713 to 1.715 |
| Birefringence | δ = 0.102 to 0.105 |
| Optical character | uniaxial negative |
| Other properties | |
| Special features | strongly pyroelectric |
Jarosite (also yellow iron ore or Raimondit ) is a common mineral from the mineral class of " Sulfate " (and relatives, see Classification ). It crystallizes in the trigonal crystal system with the composition KFe 3 3+ [(OH) 6 | (SO 4 ) 2 ], so from a chemical point of view it is a potassium - iron- sulfate with additional hydroxide ions .
Jarosite is transparent to translucent and develops tabular, pseudocubic crystals . It is mostly found in the form of small, crystalline crusts or fibrous, kidney-shaped, granular, powdery or earthy aggregates of amber-yellow to dark brown color. Uninjured crystal surfaces have a glass-like to diamond-like gloss , whereas fractured surfaces have a more resin -like gloss .
The mineral looks quite similar to limonite ( brown iron stone ) and is occasionally confused with it, especially since it weathers over time.
Etymology and history
Jarosite was first discovered near Barranco Jaroso in the Sierra Almagrera in the Spanish province of Almería and described in 1852 by August Breithaupt , who named the mineral after its type locality .
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the jarosite belonged to the mineral class of "sulfates, chromates , molybdates and tungstates " and there to the department of "anhydrous sulfates with foreign anions ", where together with alunit , ammonioalunit , Ammoniojarosit , Argentojarosit , Beaverit , Dorallcharit , Huangit , Hydroniumjarosit , Krivovichevit , Minamiit , Natroalunit , Natrojarosit , Osarizawait , Plumbojarosit and Walthierit the "Alunit-Gruppe" with the system no. VI / B.11 .
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 jarosite to the class of "sulfates (including selenates , tellurates , chromates, molybdates and tungstates)" and also to the department there the “sulfates (selenates etc.) with additional anions, without H 2 O”. This is, however, further subdivided according to the relative size of the cations involved , so that the mineral can be found according to its composition in the sub-section "With medium-sized and large cations", where it can be found together with alunite, ammonioalunite, ammoniojarosite, argentojarosite, beaverite, dorallcharite, Huangite, hydronium jarosite, minamiite, natroalunite, natrojarosite, osarizawait, plumbojarosite and walthierite the "alunite group" with system no. 7.BC.10 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns jarosite to the class of "sulfates, chromates and molybdates" and there to the category of "anhydrous sulfates with hydroxyl or halogen". Here it is together with natrojarosite, hydronium jarosite, ammoniojarosite, argentojarosite, plumbojarosite, beaverite and dorallcharite in the "alunite group (jarosite subgroup)" 02/30/05 within the subdivision " anhydrous sulfates with hydroxyl or halogen with (AB) 2 XO 4 Z q " to find.
Crystal structure
Jarosite crystallizes trigonal in the space group R 3 m (space group no. 166) with the lattice parameters a = 7.30 Å and c = 17.27 Å as well as 3 formula units per unit cell .
properties
The mineral is strongly pyroelectric , so it reacts with intermittent heating and cooling by building up an electrical voltage.
Education and Locations
As a typical secondary mineral, jarosite is formed by weathering from iron sulfides , mainly from pyrite . In addition to this, natrojarosite appears as an accompanying mineral , with which it forms a seamless series of mixed crystals . In addition, jarosite also forms pseudomorphoses according to Alunit .
In total, jarosite has been detected at over 1800 sites so far (as of 2012).
In Germany Jarosite occurred in many places in the Black Forest in Baden-Württemberg; near Hagendorf ( Waidhaus ) in Bavaria; near Kirschhausen , Richelsdorf , Biebergemünd and Essershausen in Hesse; near Müllingen and several places in the Harz Mountains in Lower Saxony; near Friedland in Mecklenburg-Western Pomerania; in several places in the Sauerland and Siegerland in North Rhine-Westphalia; in many places in the Eifel from North Rhine-Westphalia to Rhineland-Palatinate; in some places around Saarlouis in Saarland; on Petersberg near Halle , near Hasserode and Staßfurt in Saxony-Anhalt; in many places in the Saxon Ore Mountains , Upper Lusatia and near Oelsnitz / Vogtl. as well as at Ronneburg , Neumühle / Elster and Schmiedefeld am Rennsteig in Thuringia.
In Austria Jarosit was mainly found in Carinthia (Friesach-Hüttenberg, Karawanken, Kreuzeckgruppe), Lower Austria (Waldviertel), Salzburg (Hohe Tauern) and Styria (Fischbacher Alpen, Stubalpe), but was also found on Pauliberg in Burgenland, on Silberberg, the Gratlspitze and the Weißen Schrofen in Tyrol, near Eferding and Grein in Upper Austria and near Fellimännle ( Silbertal ) in Vorarlberg.
In Switzerland, the mineral was found primarily in the canton of Valais , but also near Grindelwald in the canton of Bern and near Bex and Eclépens in the canton of Vaud.
Other locations are in Afghanistan, Antarctica, Argentina, Armenia, Azerbaijan, Australia, Belgium, Bolivia, Brazil, Bulgaria, Chile, China, Denmark, the Democratic Republic of the Congo, Ecuador, Eritrea, Estonia, France, Greece, Iceland, India, Indonesia, Iran, Ireland, Italy, Japan, Canada, Kazakhstan, Kyrgyzstan, Colombia, Cuba, Madagascar, Mali, Morocco, Macedonia, Mexico, Mongolia, Namibia, the Netherlands, New Zealand, Norway, Pakistan, Papua New Guinea, Peru, the Philippines, Poland, Portugal, Romania, Russia, Sweden, Slovakia, Spain, South Africa, Taiwan, Czech Republic, Ukraine, Hungary, Uzbekistan, the US Virgin Islands, the United Kingdom (Great Britain), the United States of America (USA) and Cyprus.
Jarosite was also detected in rock samples from the Mid-Atlantic Ridge and the Juan de Fuca Ridge in the Pacific.
Jarosite was also detected on the surface of the planet Mars in March 2004 by the space probe " Opportunity " . Since jarosite can only be formed on earth with the help of water , the evidence is an indication that liquid water was present on Mars.
Jarosite is also found in large quantities in the organic marshland , which is found in the Altmarschen z. B. the German North Sea coast. When creating a soil profile, it shows up in the form of intense yellow sprinkles in the subsoil, where it precipitates due to very low pH values and the presence of iron sulphate. The mineral is also called Maibolt in the language of the region . The name is based on the freshly plowed field (Maifeld) and the superstitious idea of a goblin that turns the ground yellow. The relationship to the goblin, which has a negative connotation in popular belief, is obvious: a field where Maibolt is plowed to the surface hardly bears any plants for years and was therefore considered to have been poisoned by the earth spirit.
use
Jarosite has no significant application. The mineral is sometimes used as a yellow earth pigment in painting .
See also
literature
- JFA Breithaupt: Jarosit, jarosites kalicus , in: Berg- und Hüttenmännische Zeitung , 11th edition, JG Engelhardt, Freiberg 1852, pp. 68-69 ( PDF 386.6 kB )
- Helmut Schrätze, Karl-Ludwig Weiner: Mineralogy. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 584 .
- Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke , Stuttgart 1978, ISBN 3-432-82986-8 , pp. 603 (first edition: 1891).
- Petr Korbel, Milan Novák: Encyclopedia of Minerals . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 ( Dörfler Natur ).
- U. Schwertmann: About the occurrence and formation of jarosite in marshland (Maibolt). In: Natural Sciences. Volume 48, No. 6, 1961, pp. 159-160, doi: 10.1007 / BF00639539
Web links
- Mineral Atlas: Jarosite (Wiki)
- Seen in doubt. When the Mars robot Opportunity discovered the iron-sulfur mineral jarosite on Mars in March 2004 ... On: Wissenschaft.de on October 25, 2006
Individual evidence
- ↑ a b c d e 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. 373 .
- ↑ Webmineral - jarosites
- ↑ a b c John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols: Jarosite , in: Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 65.5 kB )
- ↑ a b c Mindat - Jarosite
- ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke , Stuttgart 1978, ISBN 3-432-82986-8 , pp. 603 (first edition: 1891).
- ↑ MinDat - Raimondite (English)
- ↑ Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1979, ISBN 3-342-00288-3 , p. 678 .
- ↑ Mindat - Localities for jarosites