Safflorite

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Safflorite
Safflorite, Calcite2-280978.jpg
Fresh, tin-white safflorite on calcite from the "Bouismas Mine", Bou Azzer , Tazenakht , Ouarzazate Province , Morocco (size of the step 3.0 cm)
General and classification
other names
  • fibrous, white cobalt (after Werner)
  • Safflower
  • Whisk gravel
chemical formula CoAs 2
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.EB.15a ( 8th edition : II / D.23)
02.12.02.11
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol orthorhombic-dipyramidal; 2 / m  2 / m  2 / m
Space group Pnnm (No. 58)Template: room group / 58
Lattice parameters a  = 5.17  Å ; b  = 5.95 Å; c  = 3.00 Å
Formula units Z  = 2
Frequent crystal faces {010}, {001}, {110}, {120}, {130}, {011}, {101}
Twinning Quintuplets according to {011}, cross-shaped penetration twins according to {101}
Physical Properties
Mohs hardness 4.5 to 5 (VHN 100  = 792–882)
Density (g / cm 3 ) measured: 7.2; calculated: 7.471
Cleavage indistinct after {100}
Break ; Tenacity uneven to scalloped
colour tin-white, tapering to dark gray
Line color grey black
transparency opaque
shine Metallic luster

Safflorite is a rather seldom occurring mineral from the mineral class of the “ sulfides and sulfosalts ” (including selenides, tellurides, arsenides, antimonides, bismuthides, sulfarsenites, sulfantimonites, sulfbismuthites). It crystallizes in the orthorhombic crystal system with the chemical composition CoA 2 , that is a cobalt - arsenide .

Safflorite is opaque in every form and only develops small, prismatic crystals , which are usually fused into star-shaped triplets with a whirl- like appearance ( whorled pebbles ). However, it also occurs in fibrous, radial-radial mineral aggregates . Crust-like adhesions with other gaits and coarse and dense masses are also known. Fresh mineral samples are tin-white in color and have a metallic sheen on the surfaces . In the air, however, they turn dark gray over time.

Etymology and history

The mineral was first mentioned in 1817 in the mineral system by Abraham Gottlob Werner , who divided the white food goblin into a fibrous, dense and knitted variety. However, there is no more detailed description of appearance and occurrence. In the same year, however, August Breithaupt also published a new edition of Hoffmann's “Handbuch der Mineralogie”, in which he gave a detailed description of the color, crystal shape and fracture behavior of the mineral under the name Radiant white Speiskobold and the “Grube Daniel” near Neustädtel (Schneeberg) (Ore Mountains, Saxony) sells. With the help of the soldering tube sample, he can also determine that the radiant white food cobalt must be a combination of cobalt and arsenic. However, a precise chemical analysis was only carried out by Friedrich Stromeyer in 1832, who was able to determine the chemical composition as CoAs 2 .

1835 replaced Breithaupt finally, the previous name of fibrous white smaltite by the final name safflorite, based on its use as a blue pigment for coloring glass and enamels, which made of cobalt ores and as safflower or safflower is called (not to be confused with likewise as safflower designated safflower ). According to Johann Albrecht Gesner (1744), the German word safflower or safflower is derived from the Latin sapphirus for the blue gemstone sapphire . Safflower would therefore be a combination of sapphiri and color (= sapphire-colored).

classification

In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , safflorite belonged to the department of "Sulphides with the molar ratio of metal: S, Se, Te <1: 1", where it was used together with Costibit , Löllingit , Nisbit , Oenit , Rammelsbergit and Seinäjokit the "Löllingite group" with the system no. II / D.23 formed.

In contrast , the 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), classifies safflorite in the category of "Metal sulfides with M: S ≤ 1: 2". 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 Anduoite , Klinosafflorite , Löllingite, Nisbit, Omeiite and Rammelsbergite the "Löllingite group" with the system no. 2.EB.15a forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns safflorite to the class of "sulphides and sulphosalts" and there in the category of "sulphide minerals". Here it is, however, together with Anduoite, Ferroselite , Frohbergite , Kullerudite , Löllingite, Markasite , Nisbit, Mattagamite , Omeiite, Rammelsbergite and Seinäjokit in the " Marcasite group (Orthorhombic: 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".

Crystal structure

Safflorite crystallizes orthorhombically in the space group Pnnm (space group no. 58) with the lattice parameters a  = 5.17  Å ; b  = 5.95 Å and c  = 3.00 Å as well as two formula units per unit cell . Template: room group / 58

properties

Safflorite theoretically has a cobalt content of 28.23% with an arsenic content of 71.77%. In naturally entstandenem Safflorit is, however, by formation of mixed crystals with Löllingit (FeAs 2 ) and / or rammelsbergite (NiAs 2 ) is always a small proportion of cobalt by iron (up to 15%) and nickel diadoch replaced .

In front of the soldering tube on the coal, the mineral largely evaporates with strong development of arsenic vapors with a typical garlic odor. A brownish black oxide remains. The smell of arsenic also occurs when smashing safflorite samples.

Modifications and varieties

The compound CoAs 2 is dimorphic and occurs naturally as monoclinic, crystallizing clinosafflorite in addition to the orthorhombically crystallizing safflorite .

Education and Locations

Safflorite crystals from Alberoda , Schlema-Hartenstein, Ore Mountains (field of view 8 mm)
Safflorite (gray) and solid silver from the "Langis Mine", Casey , Timiskaming District , Ontario, Canada ( total size of the sample : 8 × 5.5 × 2.5 cm)

Safflorite forms hydrothermally on medium- grade dykes , where it usually occurs in paragenesis with other nickel and cobalt minerals such as lollingite, nickel line , rammelsbergite and skutterudite . Safflorite can also be associated with dignified bismuth and silver . Slow weathering causes safflorite to gradually become coated with a pink crust of erythrin ( cobalt blossom )

As a rather rare mineral formation, safflorite can sometimes be abundant at various sites, but overall it is not very common. So far (as of 2013) around 270 sites are known. However, the mineral is likely to be found much more abundantly than is generally believed. For example, a large part of the "dining cobalt" in various mineralogical collections consists of safflorite.

In addition to its type locality "Grube Daniel", safflorite was also found in many other pits in the Schneeberg mining area and in general in the Saxon Ore Mountains . Other well-known sites in Germany include various pits near Wittichen , Oberwolfach and other places in the Black Forest in Baden-Württemberg; Wölsendorf in Bavaria; several places in the Hessian Odenwald ; the mining area Sankt Andreasberg and other places in the Harz Mountains from Lower Saxony to Saxony-Anhalt; the Wilder Mann mine near Müsen in North Rhine-Westphalia; various pits near Imsbach , the uranium deposit near Ellweiler and the iron / lead mine Fischbacher Werk near Niederfischbach in Rhineland-Palatinate as well as the uranium deposit near Ronneburg , the ore mine Kamsdorf and the cobalt deposit near Glücksbrunn in Thuringia.

Safflorite is also found widespread in the Cobalt - Gowganda region in the Timiskaming District in the Canadian province of Ontario and in the area around Bou Azzer (Bou Azer) in the Moroccan province of Ouarzazate .

In Austria safflorite was among others in the hut Erzberg in Carinthia, in Brunn grave area of the copper deposit Schoenberg near the village Flatschach and the zinc wall in the valley of Obert Albach ( Schladminger Tauern ) in Styria and at Silberberg in the municipality Brixlegg - Rattenberg and on the Masner Alp close Landeck in the Tyrolean Inn Valley .

In Switzerland, the mineral is known so far only from the canton of Valais , more precisely from the mines near Ayer (Val d'Anniviers) , Saint-Luc VS and Blüomatttälli .

Other locations are in Argentina, Australia, Azerbaijan, Bolivia, Brazil, Chile, China, Ecuador, France, Greece, Iran, Italy, Japan, Kazakhstan, Morocco, Mexico, Norway, Poland, Romania, Russia, Sweden, Slovakia , in Spain, South Africa, the Czech Republic, England in the United Kingdom (UK) and in several states in the United States of America (USA).

Safflorite could also be detected in rock samples from the East Pacific Ridge .

use

Safflorite is used, alongside other cobalt ores, as a raw material for the extraction of cobalt.

See also

literature

  • JFA Breithaupt : On the relation of the forms to the mixtures of crystallized bodies . In: Journal for Practical Chemistry . tape 4 , 1835, p. 249–271 ( rruff.info [PDF; 1.8 MB ; accessed on May 22, 2017]).
  • 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. 323 (food cobalt).
  • Helmut Schrätze , Karl-Ludwig Weiner : Mineralogy. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 264-266 .

Web links

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

Individual evidence

  1. ↑ a b c J. FA Breithaupt : On the relation of the forms to the mixtures of crystallized bodies . In: Journal for Practical Chemistry . tape  4 , 1835, p. 265 ( rruff.info [PDF; 1.8 MB ; accessed on May 22, 2017]).
  2. ^ A b c d Helmut Schrätze , Karl-Ludwig Weiner : Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp.  264 .
  3. ↑ a b c d e 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.  108 .
  4. ↑ Webmineral - Safflorite
  5. ↑ a b Safflorite . 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; 523  kB ; accessed on May 22, 2017]).
  6. ^ AG Werner: Abraham Gottlob Werner's last mineral system . Issued from his estate by order of the Mining Authority and provided with explanations. Ed .: A. Breithaupt. Craz & Gerlach, Carl Gerold, Freyberg, Vienna 1817, p. 25 ( strahlen.org [PDF; 226 kB ; accessed on May 22, 2017]).
  7. ↑ a b A. Breithaupt : Strahliger Weisser Speiskobold . In: CAS Hoffmann's Handbook of Mineralogy . 4.1 Edition. Craz & Gerlach, Freiberg 1817, p.  181–182 ( strahlen.org [PDF; 454 kB ; accessed on September 11, 2013]).
  8. ^ A b Thomas Witzke : The discovery of safflower at www.strahl.org
  9. ↑ JA Gesner: Historia Cadmiae Fossilis Metallicae sive Cobalti et ex illo praeparatorum Zaffarae et Smalti . In: Berolini, prostate in Officina Rudigeriana . 1744, p. 27 .
  10. ↑ 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.  331 .
  11. ↑ a b Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp.  499 (first edition: 1891).
  12. ↑ Mindat - Number of localities for safflorite
  13. ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia (=  Dörfler Natur ). Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 47 .
  14. ↑ Find location list for safflorite in the Mineralienatlas and Mindat
  15. ↑ Mindat - Safflorite discovery Escanaba Trough, Southern Gorda Ridge, Juan de Fuca Ridge complex, East Pacific Rise, Pacific Ocean