Stibioclaudetite
| Stibioclaudetite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | AsSbO 3 |
|
Mineral class (and possibly department) |
Oxides and hydroxides |
|
System no. to Strunz and to Dana |
4.CB.45 ( 8th edition : IV / C.01) 03/04/10/03 |
| Similar minerals | Claudetite |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | P 2 1 / n (No. 14, position 2) |
| Lattice parameters |
a = 4.5757 Å ; b = 13.1288 Å; c = 5.4216 Å β = 95.039 ° |
| Formula units | Z = 4 |
| Frequent crystal faces | {010}, {110}, {111}, { 1 01} |
| Twinning | fishtail-shaped twins |
| Physical Properties | |
| Mohs hardness | <2 |
| Density (g / cm 3 ) | 5.009 (calculated) |
| Cleavage | very perfect according to (010) |
| Break ; Tenacity | not specified; inelastic flexible |
| colour | colorless to slightly yellowish |
| Line color | White |
| transparency | transparent to translucent |
| shine | Diamond gloss to resin gloss |
| Crystal optics | |
| Refractive index | n > 2.00 |
Stibioclaudetite is a very rarely occurring mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the monoclinic crystal system with the idealized composition AsSbO 3 , so it is chemically seen a arsenic - antimony - oxide .
Stibioclaudetite is a typical secondary mineral and is formed in arsenic-containing non-ferrous metal deposits through the oxidation of antimony-containing primary arsenic minerals such as tennantite . It can be found at its type locality in the form of idiomorphic crystals up to 6 mm in size in the massive tennantite ore, where it is accompanied by quartz , Leiteit , Ludlockite and Smithsonite .
The type locality of the mineral is a leading area within the so-called second or the so-called third oxidation zone of the Tsumeb Mine near Tsumeb , Oshikoto region , Namibia .
Etymology and history
After the mineral dealer David W. Bunk had acquired an unusual mineral specimen from the "Tsumeb Mine" with well-developed conductivity as well as ludlockite and quartz, all attempts to identify a colorless mineral that was also present in the paragenesis failed. It was shown by Raman spectroscopy that there were three separate crystals of this unknown mineral. Similarities in the Raman spectrum of this mineral with Leiteit indicated that it is an As 3+ -containing structure. Preliminary investigations with energy-dispersive X-ray spectroscopy on a scanning electron microscope revealed the presence of As, Sb and O (and the absence of all other elements with atomic numbers> 8). All analyzes indicated that a new mineral was present so further studies were carried out to fully characterize the material. The new mineral was presented to the International Mineralogical Association (IMA), which approved it in 2007 under the tentative designation IMA 2007-028. The first scientific description of this mineral as stibioclaudetite ( English Stibioclaudetite ) was made in 2009 by an American research team with Marcus J. Origlieri , Robert T. Downs , William W. Pinch and Gary L. Zito in the American journal The Mineralogical Record . Because the new mineral is an ordered Sb-substituted analogue of claudetite and is structurally closely related to claudetite, the authors named it stibioclaudetite.
The type material for stibioclaudetite is listed under catalog no. 174,550 in the collection of the Smithsonian Institution belonging to National Museum of Natural History , Washington, DC , USA , kept.
Claudetite from the "Tsumeb Mine" was first described in 1958 as "colorless, flexible platelets with plaster-like cleavage" . Since stibioclaudetite has an identical morphology, the “claudetite” crystals known from the “Tsumeb Mine” should be checked, as they could actually hide the then unknown mineral stibioclaudetite.
classification
The outdated, but partly still in use, 8th edition of the mineral classification according to Strunz does not yet list the stibioclaudetite. He would presumably for mineral class of "oxides and hydroxides" and then to the Department of "oxides with the molar ratio of metal: oxygen = 2: 3 (M 2 O 3 and related compounds)" include, where he together with Auroantimonat , Claudetit and Valentinit the "Claudetite-Valentinit-Gruppe" with the system no. IV / C.01 .
The 9th edition of Strunz's mineral systematics, which has been valid since 2001 and is used by the IMA, also assigns stibioclaudetite to the class of "oxides", but there in the department of "oxides with the molar ratio of metal: oxygen = 2: 3, 3: 5 and comparable "a. In addition, this section is further subdivided according to the size of the cations involved , so that the mineral can be found according to its composition in the sub-section “With medium-sized cations”, where it is only together with claudetite the “claudetite group” with the system no. 4.CB.45 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns stibioclaudetite to the class of "oxides and hydroxides" and there into the "oxides" category. Here he is in the "claudetite group" with the system no. 04.03.10 and the other members claudetite and bismite can be found within the subsection of " Simple oxides with a cation charge of 3+ (A 2 O 3 ) ".
Chemism
Ten microprobe analyzes on stibioclaudetite from the "Tsumeb Mine" resulted in mean values of 45.15% As 2 O 3 and 55.77% Sb 2 O 3 . On the basis of three oxygen atoms , the empirical formula As 1.088 Sb 0.912 O 3 was calculated from them , which was simplified to AsSbO 3 . This ideal formula requires contents of 40.43% As 2 O 3 and 59.57% Sb 2 O 3 .
Stibioclaudetite is the ordered analogue of the As 3+ -dominated claudetite, As 2 O 3 , with substitution of Sb 3+ on an As position.
Crystal structure
Stibioclaudetite crystallizes monoclinically in the space group P 2 1 / n (space group no. 14, position 2) with the lattice parameters a = 4.5757 Å ; b = 13.1288 Å; c = 5.4216 Å and β = 95.039 ° as well as four formula units per unit cell .
The crystal structure of Stibioclaudetit consists of corrugated layers of trigonal As 2 O 3 - and Sb 2 O 3 - pyramids arranged in an ordered, alternating form. The corrugated layers are stacked in the direction of [010]. The very perfect cleavage according to (010) results from the relatively weak bond between these layers. There are two different positions for As atoms in the crystal structure: As (1) and As (2). Antimony, with its ionic radius which is significantly larger than that of arsenic, only substitutes arsenic in the As (2) position.
Stibioclaudetite is isotypic (isostructural) to its Sb 3+ -free analogue claudetite, with which it forms a complete series of mixed crystals . It is the natural equivalent of the synthetic AsSbO 3 known since 1983 .
properties
morphology
Stibioclaudetite occurs at its type locality in the form of tabular, gypsum-like crystals up to 6 mm in length, which can be arranged in parallel, intergrown aggregates. The lateral pinacoid {010} determines the costume , {110}, {111} and { 1 01} have been observed on other surface shapes (see the crystal drawing opposite). From "Wet Swine Gill", Caldbeck Fells, Cumbria, United Kingdom , also in plaster-like, tabular to prismatic crystals up to 5 mm in length, which sometimes form fish-tail-shaped twins. In addition to its occurrence in the form of idiomorphic crystals in cavities of the antimony-rich quartz vein, stibiotantalite was also found in "Wet Swine Gill" in polycrystalline masses up to 1 cm in size in hairline cracks in quartz blocks at the base of the oxidation zone. From the slag deposits of Weitschach in the form of up to 1 mm large, latte crystals with roof-shaped end surfaces that have grown together to sub-parallel aggregates. Due to the morphology of the mineral, the Stibioclaudetite this occurrence easily with Anglesite or barite confused.
physical and chemical properties
The crystals of the Stibioclaudetite are colorless to slightly yellowish, but their line color is always white. The surfaces of the transparent to translucent stibioclaudetite show a diamond to resin- like sheen , which agrees very well with the values for light refraction (n> 2.00).
Stibioclaudetite has a very perfect cleavage according to (010). Its behavior at break is similar to that of molybdenite, inelastically flexible. With a Mohs hardness of <2, the mineral is one of the soft minerals and, like the reference minerals plaster of paris or halite, can be scratched with the fingernail.
Measured values for the density of the stibioclaudetite do not exist. The calculated density for stibioclaudetite is 5.009 g / cm³. Stibioclaudetit still in the shortwave is neither in the long UV light , a fluorescent .
Education and Locations
Stibioclaudetite forms in the oxidation zone of ore deposits , with the arsenic likely originating from the weathering of the arsenic pale ore tennantite . Since tennantite from the "Tsumeb Mine" also contains substantial amounts of antimony and zinc , both the antimony content of the stibioclaudetite and the zinc content of the accompanying control room may have been released during the implementation of the tennantite. From the synthesis temperatures for synthetic monoclinic AsSbO 3 (347 ° C), a formation temperature for stibioclaudetite in the "Tsumeb Mine" between 300 ° C and 400 ° C is deduced. For the "Wet Swine Gill" occurrence near Caldbeck Fells, it is assumed that stibioclaudetite was formed under supergenic conditions at low temperatures and a relatively low oxidation potential from solutions that are rich in arsenic and antimony in their intermediate oxidation states As (III) and Sb (III) were.
Typical accompanying minerals in the type locality of the “Tsumeb Mine” are quartz, Leiteit, Ludlockite and Smithsonite, which all occurred in a druse in the massive tennantite ore. In Borgofranco to Stibioclaudetit found along with Villyaellenit , Arsenolith , Pikropharmakolith and Parasymplesit in a matrix of galena and pyrite . At the “Wet Swine Gill” location near Caldbeck Fells, it coats stibnite and sulphides containing antimony as well as sulphosalts and is in turn coated with senarmontite , valentinite and sulfur . It rarely contains tiny inclusions of red metastibnite . In Weitschach it occurs in the "secondary slag phases".
As a very rare mineral formation, stibioclaudetite could only be described from four sites so far (status 2018). The type locality for stibioclaudetite is the "Tsumeb Mine" near Tsumeb , Oshikoto region , Namibia . The exact point of discovery is unknown, but due to the paragenesis with conductivity, which is unknown from the first oxidation zone, it must lie in the area of the second or so-called third oxidation zone. The paragenesis of the Stibioclaudetite from the "Tsumeb Mine", which differs significantly from that of the Leiteit type stage, indicates, however, a different location than the previously known finds of Leiteit in the "Tsumeb Mine".
The second place where stibioclaudetite was found is the "Miniere di Borgofranco" near Biò, Borgofranco d'Ivrea in the historical Canavese area , Turin , Piedmont region , Italy , which is known for the occurrence of tubulite . In addition, from the slag deposits in the area around the Maria Waitschach church near Waitschach not far from Hüttenberg , Friesach region - Hüttenberg, Carinthia , Austria . Finally, from a stibnite and Berthierit leading vein in the fine-grained sedimentary rocks of Ordovician Skiddaw Group on the hill at Coombe "Wet Swine Gill" in the Caldbeck Fells in the English county of Cumbria in the UK .
Locations for stibioclaudetite from Germany and Switzerland are therefore unknown.
use
Due to its rarity, stibioclaudetite is a sought-after mineral by mineral collectors, but otherwise of no practical importance.
See also
literature
- Marcus J. Origlieri, Robert T. Downs, William W. Pinch, Gary L. Zito: Stibioclaudetite, AsSbAs 3 a new mineral from Tsumeb, Namibia . In: The Mineralogical Record . tape 40 , no. 3 , 1985, pp. 209–213 ( rruff.info [PDF; 3.4 MB ; accessed on August 25, 2018]).
Web links
- Mineral Atlas: Stibioclaudetite (Wiki)
- Webmineral - Stibioclaudetite ( accessed August 25, 2018)
- Mindat - Stibioclaudetite (English) ( accessed August 25, 2018)
- Tsumeb.com - Stibioclaudetite ( accessed August 25, 2018)
- Database-of-Raman-spectroscopy - Stibioclaudetite (English) ( accessed August 25, 2018)
- American-Mineralogist-Crystal-Structure-Database - Stibioclaudetite ( accessed August 25, 2018)
Individual evidence
- ↑ a b c d e f g h i j k David I. Green, Andrew G. Tindle, Tim Neall, C. Mike Leppington: Stibioclaudetite, a first British occurrence, from Wet Swine Gill, Caldbeck Fells, Cumbria . In: Journal of the Russell Society . tape 17 , 2014, p. 57–61 ( russellsoc.org [PDF; 3.3 MB ; accessed on August 25, 2018]).
- ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am Marcus Jason Origlieri, Robert T. Downs, William W. Pinch, Gary L. Zito: Stibioclaudetite, AsSbAs 3 a new mineral from Tsumeb, Namibia . In: The Mineralogical Record . tape 40 , no. 3 , 2009, p. 209–213 ( rruff.info [PDF; 3.4 MB ; accessed on August 25, 2018]).
- ↑ a b c d e Uwe Kolitsch, Franz Brandstätter, Fritz Schreiber, Roland Fink, Chris Auer: The mineralogy of the globally unique slag from Waitschach, Carinthia . In: Annals of the Natural History Museum in Vienna, Series A . tape 115 , 2013, p. 19–87 ( nhm-ien.ac.at [PDF; 6.5 MB ; accessed on August 25, 2018]).
- ↑ Hugo Strunz, Gerhard Söhnge, Bruno H. Geier: Stottite, a new germanium mineral, and its paragenesis in Tsumeb . In: New yearbook for mineralogy, monthly books . tape 1957 , 1957, pp. 85-96 .
- ↑ a b Marcus Jason Origlieri: Crystal chemistry of selected Sb, As and P minerals (dissertation, Faculty of the Department of Geosciences, University of Arizona) . University of Arizona, Tucson 2005, pp. 1–86 ( arizona.edu [PDF; 865 kB ; accessed on August 25, 2018]).
- ^ A b Doris Bodenstein, Axel Brehm, Peter G. Jones, Einhard Schwarzmann, George M. Sheldrick: Presentation and crystal structure of monoclinic arsenic (III) antimony (III) oxide, AsSbO 3 / Preparation and Crystal Structure of Monoclinic Arsenic (III) Antimony (III) Oxide, AsSbO 3 . In: Zeitschrift fur Naturforschung . tape 38 , no. 8 , 1983, p. 901-904 , doi : 10.1515 / ZNB-1983-0801 ( degruyter.com [PDF; 3.2 MB ; accessed on August 25, 2018]).
- ↑ H. Moritz: The sulfidic ores of the Tsumeb mine from the outgoing to the XVI. Sole (-460 m) . In: New Yearbook for Mineralogy, Geology and Paleontology, Beil.-Bd. Abt. A . tape 67 , 1933, pp. 118-154 .
- ↑ a b Italo Campostrini, Bruno Martini, Adrio Salvetti, Giovanni Dalla Fontana, Matteo Boscardin, Pierluigi Ambrino, Marco E. Ciriotti: Stibioclaudetite dalle gallery inferiori di Biò, Borgofranco d'Ivrea (Torino) . In: Micro . tape 10 , no. 3 , 2012, p. 142-144 .
- ↑ a b Italo Campostrini, Francesco Demartin, Bruno Martini, Adrio Salvetti, Giovanni Dalla Fontana, Matteo Boscardin, Pierluigi Ambrino, Marco E. Ciriotti: Villyaellenite dalle gallerie inferiori di Biò, Borgofranco (Torino) [GMT 2014 Giornate Mineralogiche di Tavagnasco, 6 -8 giugno 2014] . In: Pliny . tape 40 , 2014, p. 170 ( researchgate.net [PDF; 102 kB ; accessed on July 20, 2018]).
- ↑ Mindat - number of sites for Stibioclaudetite (English) ( accessed on August 25, 2018)
- ↑ List of locations for stibioclaudetite in the Mineralienatlas and Mindat ( accessed on August 25, 2018)
- ↑ a b Mindat - Stibioclaudetite (English) ( accessed August 25, 2018)