Lollingite
| Lollingite | |
|---|---|
 (size ~ 2.5 mm) |
|
| General and classification | |
| other names |
|
| chemical formula | FeAs 2 |
|
Mineral class (and possibly department) |
Sulphides and sulphosalts - metal: sulfur (selenium, tellurium) <1: 1 |
|
System no. to Strunz and to Dana |
2.EB.15a ( 8th edition : II / D.23) 02.12.02.09 |
| Similar minerals | Arsenopyrite (arsenic gravel), gersdorffite |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-dipyramidal 2 / m 2 / m 2 / m |
| Room group (no.) | Pnnm (No. 58) |
| Lattice parameters | a = 5.243 Å ; b = 5.978 Å; c = 2.9783 Å |
| Formula units | Z = 2 |
| Twinning | mainly twinned after {011}, also triplets |
| Physical Properties | |
| Mohs hardness | 5 to 5.5 |
| Density (g / cm 3 ) | 7.0 to 7.4 |
| Cleavage | clearly after (001) |
| Break ; Tenacity | uneven, brittle |
| colour | silver-white, tapering gray |
| Line color | gray to black |
| transparency | opaque |
| shine | Metallic luster |
| magnetism | Hardly melting into a magnetic ball in front of the soldering tube |
| Other properties | |
| Special features | when freshly broken it is clearly lighter than arsenopyrite |
Löllingite , also outdated as arsenic iron or arsenic lime , more rarely known under its chemical name iron arsenide , is a rather seldom occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the orthorhombic crystal system with the chemical composition FeAs 2 and develops either prismatic crystals or massive aggregates of silver-white color, which turn gray after a while in the air. However, the fresh mineral quarry is lighter in color than the otherwise similar arsenopyrite .
Etymology and history
Löllingit was named after its type locality (first place of discovery) Lölling in Carinthia . It was first found and described in 1845 by Wilhelm Ritter von Haidinger .
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the lollingite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides with the molar ratio of metal: sulfur, selenium, tellurium <1: 1", where together with the minerals costibite , nisbit , oenite , rammelsbergite , safflorite and Seinäjokit the lollingite group with the system no. II / D.22 .
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 lollingite to the class of “sulphides and sulphosalts” and there in the section of “metal sulphides with metal (M): sulfur (S) ≤ 1: 2 “. However, this is further subdivided according to the exact molar ratio and the predominant metals in the compound, so that the mineral can be found in the sub-section "M: S = 1: 2, with Fe, Co, Ni, PGE etc." according to its composition , where, together with alloclasite, anduoite , clinosafflorite, costibite, krutovite, nisbit, oenite, omeiite , paracostibite, pararammelsbergite, rammelsbergite and safflorite, the "Löllingite group" with the system no. 2.EB.15 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the lollingite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here it is together with marcasite , ferroselite , Frohbergite, hastite, mattagamite, kullerudite, omeiite , anduoite , seinäjokite, safflorite, rammelsbergite and nisbit in the "marcasite group (Orthorhombian: Pnnm )" with the system no. 02.12.02 within the subsection " Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 1: 2 ".
Modifications and varieties
As Glaukopyrit one is cobalt-containing variety of Löllingit referred. It is miscible with safflorite, CoAs 2. However, this miscibility is not complete. Iron can also be partially exchanged for nickel and arsenic for sulfur.
Education and Locations
Löllingite forms either in igneous rocks such as pegmatite or as a minor component in hydrothermal veins. It is accompanied by calcite , nickeline , pharmacosiderite , siderite , skutterudite and bismuth, among others .
As a rather rare mineral formation, lollingite can sometimes be abundant at various sites, but overall it is not very common. Around 580 sites are known to date. In addition to its type locality Lölling, the mineral occurred in Austria, among other places, in several places on the Hüttenberger Erzberg , near Sankt Martin am Silberberg , on the Saualpe and on the Markogel in Carinthia ; on the Schlossberg near Gloggnitz in Lower Austria; in the Gastein Valley and on the Rotgüldensee in Salzburg as well as on the Semmering Basis Tunnel ( Semmering Pass ) near Dürrhof, on the Vetterspitzen and on the Zinkwand in the Schladminger Tauern .
In Germany, Löllingite was found mainly in the Black Forest ( Wittichen , Oberwolfach ), in the Spessart (Hartkoppe, Schöllkrippen ), in the Bavarian Forest , in the Odenwald , in the Harz ( Rammelsberg , Sankt Andreasberg ), in the Siegerland , in the Ore Mountains and in the Vogtland .
In Switzerland, the mineral has so far only been found in the canton of Valais , more precisely near Ayer (Val d'Anniviers) , Saint-Luc VS , Pipjitälli and Salanfe .
Other locations include Egypt, Australia, Bolivia, Brazil, Bulgaria, Chile, China, Finland, France, Georgia, Ghana, Greece, Greenland, Guinea, India, Iran, Ireland, Italy, Japan, Canada, Kazakhstan, Kyrgyzstan, Korea, Kosovo, Democratic Republic of the Congo, Morocco, Mexico, Mongolia, Namibia, Norway, Pakistan, Poland, Portugal, Romania, Russia, Sweden, Slovakia, Spain, South Africa, Czech Republic, Tajikistan, Ukraine, Hungary in the United Kingdom (Great Britain) and in the United States of America (USA).
Löllingite could also be detected in rock samples from the East Pacific Ridge .
Crystal structure
Löllingite crystallizes in the orthorhombic crystal system in the space group Pnnm (space group no. 58) with the lattice parameters a = 5.243 Å , b = 5.978 Å and c = 2.9783 Å as well as two formula units per unit cell .
use
Löllingite is used as a raw material for the extraction of arsenic .
See also
literature
- Martin Okrusch, Siegfried Matthes: Mineralogy. An introduction to special mineralogy, petrology and geology . 7th fully revised and updated edition. Springer Verlag, Berlin et al. 2005, ISBN 3-540-23812-3 , pp. 40 .
- Petr Korbel, Milan Novák: Encyclopedia of Minerals . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 47 ( Dörfler Natur ).
- Thomas Drapela: Incident light optical investigations on the rhombic minerals marcasite (FeS 2 ) and lollingite (FeAs 2 ). Dissertation at the University of Vienna, Vienna, 1990
Web links
Individual evidence
- ↑ a b c Webmineral - Lollingite (English)
- ↑ a b c d American Mineralogist Crystal Structure Database - Lollingite
- ↑ a b 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. 176, 265 .
- ↑ a b Mindat - Glaucopyrite (English)
- ↑ John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols: Löllingite , in: Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 60.3 kB )
- ↑ Skage R. Hem, Emil Makovicky: The system Fe-Co-Ni-As-S. II. Phase relations in the (Fe, Co, Ni) As 1.5 S 0.5 section at 650 ° and 500 ° C , in: The Canadian Mineralogist , Volume 42 (2004), pp. 63–86 ( PDF 1 , 6 MB )
- ↑ a b Mindat - Localities for Löllingite