Pucherite
| Pucherite | |
|---|---|
 |
|
| General and classification | |
| other names |
anhydrous vanadium bismuth oxide |
| chemical formula | Bi [VO 4 ] |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.AD.40 ( 8th edition : VII / A.19) 04/38/06/01 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-dipyramidal; 2 / m 2 / m 2 / m |
| Space group | Pnca (No. 60, position 3) |
| Lattice parameters | a = 5.33 Å ; b = 5.05 Å; c = 12.00 Å |
| Formula units | Z = 4 |
| Frequent crystal faces | Pinacoids {001}, {100}, prisms {011}, {021}, {210}, dipyramids {111}, {112}, {211}, {522} |
| Twinning | Yes |
| Physical Properties | |
| Mohs hardness | 4th |
| Density (g / cm 3 ) | 6.69 (calculated) |
| Cleavage | marked after (001) |
| Break ; Tenacity | slightly mussel-like; brittle |
| colour | reddish brown to brownish red; light yellowish brown, hyacinth red, dark brownish black; light yellow, yellow-orange, red-brown, light and dark brown |
| Line color | yellow to ocher yellow |
| transparency | transparent to opaque |
| shine | Glass to diamond gloss |
| Crystal optics | |
| Refractive indices |
n α = 2.41 n β = 2.50 n γ = 2.51 |
| Birefringence | δ = 0.1 |
| Optical character | biaxial negative |
| Axis angle | 2V = 19 ± 5 ° (measured) |
| Other properties | |
| Chemical behavior | Easily soluble in HCl to a deep red liquid with evolution of chlorine |
Pucherite is a rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates " with the chemical formula Bi [VO 4 ]. From a chemical point of view, pucherite is therefore a bismuth vanadate .
The mineral crystallizes in the orthorhombic crystal system and develops isometric, tabular and needle-like crystals up to 5 mm in size perpendicular to the c-axis , which often have wavy curved surfaces. There are also coatings of tiny crystals as well as radial to spherical groups and rough, ocher-like mineral aggregates .
Etymology and history
As a result of the extraordinarily high prices for bismuth, the old Pucher pit in the mine field of Wolfgang Maaßen in today's Schneeberg district of Neustädtel in the Ore Mountains was reopened in 1868 and the Alexander Spat was opened after a new shaft, the Pucher shaft, had been sunk . In the same year, a mineral was found that was found in the mineral deposit of the Freiberg Mining Academy at druid places in the Ganges, on crevices of the mined "Bismutockers" ( bismuthite ) and in the adjacent rock .
The Freiberg mineralogist Albin Weisbach stated :
“In June 1871, the local mining academy mineral defeat was given a step by Mr. Graff in Neustädtel, which had many small, indistinct crystals of a demantic brown mineral and which was presented to me for inspection by the board of directors, Mr. Factor Wappler. According to the shine and color, as well as the place of discovery, the mineral could have been mistaken for a siliceous bismuth heart ( eulytin ) [...]. Therefore, I spoke in the first moments of the same for a brown variety of the of Breithaupt established in 1832 Atelestit on, but then the colored stroke due for a new bismuth salt, is included in which a chromatic base or acid. With the extremely small amount available, I approached my colleague, Professor Th. Richter, with the request to examine the behavior of the soldering tube and thus at least determine the qualitative composition. Professor Richter fulfilled my request immediately and found the reactions of vanadium and bismuth while I was still there, and thus recognized the body as vanadic acid bismuth, a compound that was not yet known from nature.
Knowing this, immediately afterwards Mr. A. Frenzel , assistant at the local Königl. Hüttenlaboratorium, an excursion to Neustädtel to see Mr. Graff's shift supervisor, and brought a large number of steps with him, which presented clearer crystals of the same body, immediately showing the character of the rhombic system. I voluntarily left the publication of the characteristics [...] of the specie to Mr. Frenzel, which we named Pucherit at the request of Mr. Graff after the shaft (Puscherschacht) (sic!) Of the pit in whose neighborhood it occurred. "
The type locality of the Pucherite is therefore the Pucher-Richtschacht of the Pucher mine in the mine field of Wolfgang Maaßen in Schneeberg-Neustädtel, Ore Mountains, Saxony. Type material for the mineral is not defined.
classification
In the 8th edition of the mineral systematics according to Strunz , which is out of date, but still in use , pucherite belonged to the division of "anhydrous phosphates [PO 4 ] 3− , without foreign anions ", where together with dreyerite and clinobisvanite it belongs to the unnamed group VII / A. 19 forms.
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 pucherite to the category of “phosphates etc. without additional anions; without H 2 O “. However, this is further subdivided according to the relative size of the cations involved and the molar ratio of the additional anions to the phosphate, arsenate or vanadate complex (RO 4 ), so that the mineral can be found in the subsection “With only large cations” according to its composition where the unnamed group with the system no. 8.AD.40 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns pucherite to the class of "phosphates, arsenates and vanadates" and there to the category of "anhydrous phosphates, etc., with hydroxyl or halogen". Here he is to be found as the sole member of the unnamed group April 38, 2006 within the subdivision anhydrous phosphates etc., A + XO 4 .
Crystal structure
Pucherite crystallizes in the orthorhombic crystal system in the space group Pnca (space group no. 60, position 3) , with the lattice parameters a = 5.33 Å ; b = 5.05 Å and c = 12.00 Å as well as four formula units per unit cell .
The crystal structure of Pucherit consists of VO 4 - tetrahedra and BiO 8 - dodecahedra with triangular faces. Each dodecahedron shares one edge with a tetrahedron and two edges with neighboring dodecahedra. The BiO 8 dodecahedra also share corners with tetrahedra and dodecahedra, whereas there is no link between the tetrahedra. A comparison of the structure of pucherite with BiVO 4 of the fergusonite and scheelite types shows that these structures are all similar in that they consist of VO 4 tetrahedra and BiO 8 dodecahedra. With regard to the connection between the polyhedra, however, the pucherite differs from the other types. While the dodecahedron in the pucherite shares two edges with two other dodecahedra and one edge with a tetrahedron, the dodecahedra in the fergusonite or scheelite structure share four edges with neighboring dodecahedra and none with a tetrahedron.
properties
morphology
At the type locality, Pucherite forms mostly isometric crystals up to 5 mm in size, the habit of which is reminiscent of that of the crystals of the Euchroit or that of the crystals of brookite and columbite. The surfaces - with the exception of {001} - are sometimes curved wavy.
Due to the dominance of a prism, the pucherite crystals have a columnar habit, due to the dominance of the base {001} a tabular habit, due to the dominance of {110} a needle-like habit and due to the dominance of {111} a dipyramidal habit. Common surface shapes are the pinacoids {100}, {001} and {010}, the prisms {011}, {021} and {210} as well as the dipyramids {111}, {112}, {211} and {522} (see also the crystal drawings shown). The surfaces of the dipyramid {111} are often striped parallel to the edge between {001} and {100} and structured like a mosaic. The crystals are often not uniform, but rather composed of several - mostly not exactly parallel - individuals, but without noticeable twinning. This structure causes the uneven nature of the crystal faces.
During morphological investigations on a total of 4,207 pucherite crystals from Schneeberg, Sosa and Ullersreuth, a total of eight main crystal costumes were endured, with 17 different crystal forms being involved in their structure. Seven of these crystal costumes were identified on Schneeberger Pucheriten . The crystals from Reichenbach, on the other hand, are almost exclusively tabular, rarely pyramidal and have only five different shapes: {001}, {111}, {011}, {013} and {110}. Depending on the dominance of {111} and {001} alone or in combination with {011}, the crystals show a square or a decidedly diamond-shaped outline when viewed from above.
physical and chemical properties
The color of the crystals and aggregates of the pucherite is brownish-red to reddish-brown in Schneeberg, in Reichenbach, depending on the thickness of the panels, light yellow, yellow-orange, red-brown or light and dark brown. Pucherite is yellow-brown in transmitted light. The line color of the transparent to opaque pucherite, on the other hand, is always yellow or ocher yellow. The surfaces of the pucherite crystals have a glass-like to diamond-like sheen .
The mineral shows a very perfect cleavage after the base (001), but breaks due to its brittleness similar to glass or quartz , whereby the break edges are slightly scalloped. With a Mohs hardness of 4, pucherite is one of the medium-hard minerals that, like the reference mineral fluorite, can be easily scratched with a pocket knife. The calculated density of the mineral is 6.69 g / cm 3 .
In front of the soldering tube in the glass bulb, Pucherite behaves violently crackling. The mineral melts on charcoal and creates a yellow coating of bismuth oxide, with soda you get granules of metallic bismuth. The cooled phosphorus salt bead appears pale yellow in the oxidizing flame, chrome green in the reducing flame, and when tin is added, the bead turns black. The oxidized borax bead shows a green-yellow color after cooling, the reduced one is brown when hot and retains this color even after cooling. In hydrochloric acid , the mineral dissolves very easily with the development of chlorine to a deep red liquid which turns green when standing (or immediately when diluted with water). With ammonia , a yellowish to gray-white precipitate of vanadic acid-containing bismuth oxide hydrate separates.
Modifications and varieties
The compound BiVO 4 is trimorphic and occurs in nature in addition to the orthorhombic crystallizing pucherite as monoclinic crystallizing clinobisvanite and as tetragonal crystallizing dreyerite . Pucherite is the natural vanadate-dominant analogue of the phosphate- dominated ximengite and the arsenate-dominated minerals rooseveltite and tetrarooseveltite .
When heated to over 773 K, the structure of the pucherite changes into BiVO 4 with a tetragonal scheelite structure. When it cools down, the scheelite structure changes into a BiVO 4 phase with a monoclinic fergusonite structure. From this it was deduced that pucherite may not be a stable phase in the Bi 2 O 3 - V 2 O 5 system , but is stabilized by small proportions of non-formula elements.
Education and Locations
Pucherite is a rare alteration product of primary bismuth minerals and forms secondarily in the oxidation zone of hydrothermal bismuth-bearing ore deposits . Occasionally it also occurs in zoned granite pegmatites, where it arises as an oxidation product of native bismuth .
In the case of pucherite of the type locality, the accompanying uranium minerals were originally assumed to be the origin of the vanadium . Later, however, the vanadium was derived from the peat bog waters, as the pits of the Pucher pit had been under water from the neighboring peat bogs for 200 years before they were reopened, and Pucherite crystals only formed near pits filled with such water. For some time, however, it has been assumed that ascending thermal baths with a high redox potential have mobilized the vanadium required for the formation of vanadates from the neighboring black slate and graptolite slate .
At the type locality, Pucherite is associated with Bismutite , Beyerite , Schumacherite , Petitjeanite , Schlegelite , Sillénite , Asbolan and Quartz . Accompanying minerals in the "Sosaer Glück" mine, Sosa near Eibenstock , are solid bismuth, quartz, "bismuth ocher" (bismuthite) and eulytin, and at Ullersreuth bismuthine , solid bismuth and bismuth ferrit . In pegmatites like Londonderry with bismoclite and other bismuth oxidation minerals.
Pucherite has only been described as a rare mineral formation from a few sites, but it can be somewhat more common in some localities. So far (as of 2016) around 50 sites are known.
In addition to its type of locality, Pucherit in Schneeberg is also known from the “Sauschwart”, “Siebenschlehen” (Name-Jesu-Stollen), “Güldener Falk” and “Hope” pits. It also appeared on the pits “Sosaer Glück”, Sosa near Eibenstock, and “Himmelfahrt” near Johanngeorgenstadt (all Erzgebirge , Saxony ). Also from Uranschurf Tirpersdorf in Vogtland and the "Arme Hilfe" mine near Ullersreuth in Thuringia and from point 8.0 on the Borstein cliff near Reichenbach , a district of Lautertal (Odenwald) in the Odenwald (Hesse) and in the same silicified barite dike at three other points Pucherit is known in the Hohenstein area near Gadernheim . Another well-known site is the Clara mine in the Rankach valley near Oberwolfach in the Black Forest (Baden-Württemberg).
In the United States, Pucherite was found in the "Pala Chief Mine" on Chief Mountain , the "Stewart Mine" on Tourmaline Queen Mountain in the Pala District and the "Little Three Mine" near Ramona in San Diego County of California and in the United States "Harding Mine" in the Picuris District of Taos County in New Mexico.
In Brazil, the mineral originated in the "Lavra da Posse" near São José de Brejaúba near Conceição do Mato Dentro in the state of Minas Gerais .
In Africa, Pucherite formed in the Mutala pegmatite area near Alto Ligonha ( Zambezia Province ) in Mozambique , in the “Golconda Prospect” near Harare in Zimbabwe and the “Rubikon Mine” near Karibib near the Okongava East 72 farm in the Namibian region of Erongo . The mineral was also found on the African island of Madagascar in Ambatomalaza in the Sahatany pegmatite field (Mt. Ibity area) and the pegmatite Ampangabé in the Faratsiho district in the Vakinankaratra region .
In Australia the mineral is known from the lithium deposit Londonderry near Nepean (Coolgardie Shire) in Western Australia and from Morass Creek north of Benambra in Victoria .
Other sites are in the Czech Republic and Japan. Locations in Switzerland and Austria are not known.
use
As a pigment
Bismuth vanadate is an inorganic, very greenish yellow pigment and is one of the most important substitutes for the inorganic yellow pigments used in the past and now classified as toxic, lead chromate PbCrO 4 and cadmium sulfide CdS. Pucherite is, however, just like its polymorphs clinobisvanite and dreyerite, for industrial production this pigment does not matter.
As a raw material
Pucherite with end-link composition consists of about 72% Bi 2 O 3 and about 28% V 2 O 5 . Due to its rarity, the mineral is technically completely insignificant as a raw material for these elements, but it is a coveted mineral for the mineral collector.
See also
literature
- August Frenzel (1871): Mineralogical: 1. Pucherite. In: Journal for practical chemistry , Volume 112, pp. 227-231 ( PDF, 301 kB ).
Web links
- Mineral Atlas: Pucherite (Wiki)
- Mindat - Pucherite
- Webmineral - Pucherite
- Database-of-Raman-spectroscopy - Pucherite
- American-Mineralogist-Crystal-Structure-Database - Pucherite
Individual evidence
- ↑ a b c d e f g h i j August Frenzel (1871): Mineralogical: 1. Pucherit. In: Journal for practical chemistry , Volume 112, pp. 227-231 ( PDF, 301 kB ).
- ↑ 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. 437 .
- ^ A b August Frenzel : Communications to Professor Geinitz. Freiberg, July 30, 1872 (on pucherite, hypochlorite, bismuth ferrite) . In: New Yearbook for Mineralogy, Geology and Palaeontology . tape 1872 . Swiss beard, Stuttgart 1872, p. 514-517 ( available online in New Yearbook for Mineralogy, Geology and Palaeontology. Pp. 514 f. In the Google book search).
- ↑ a b c d e f g h i j Pucherite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF, 64 kB ).
- ^ A b c d Klaus Petitjean, Klaus Belendorff: Reichenbach in the Odenwald: The minerals from the point of discovery 14.0 . In: Lapis . tape 25 , no. 2 , 2000, pp. 13-30 .
- ^ August Frenzel : Mineralogical Lexicon for the Kingdom of Saxony . 1st edition. Verlag von Wilhelm Engelmann, Leipzig 1817, p. 42–44 ( available online in Mineralogical Lexicon for the Kingdom of Saxony. Pp. 42–44 in the Google book search).
- ^ Albin Weisbach : Mineralogical notes: 1. Pucherit . In: Yearbook for mining and metallurgy in the Kingdom of Saxony . tape 1874 . Craz & Gerlach, Freiberg 1874, p. 249–250 ( available online in the yearbook for mining and metallurgy in the Kingdom of Saxony for the year 1874. P. 249 f. In the Google book search).
- ↑ a b J. Granzin, D. Pohl (1984): Refinement of pucherite, BiVO 4 . In: Zeitschrift für Kristallographie , Volume 169, pp. 289–294 ( PDF, 232 kB ).
- ^ A b Carl Hintze : Handbook of Mineralogy. First volume. Fourth department department. 1st half . 1st edition. Verlag Veit & Co., Leipzig 1933, pp. 377-381.
- ^ A b Emil W. Fischer, Will Kleber , J. Sommer (1984): About Pucherite with special consideration of the occurrences in the mesothermal BiCoNi dikes of southwest Saxony. In: Chemie der Erde , Volume 19, pp. 361-385.
- ^ August Frenzel : Communications to Professor Geinitz. Freiberg, December 8th, 1872 (creation of Pucherit) . In: New Yearbook for Mineralogy, Geology and Palaeontology . tape 1872 . Swiss beard, Stuttgart 1872, p. 939 ( available online in New Yearbook for Mineralogy, Geology and Palaeontology. P. 939 in the Google book search).
- ^ Friedrich Leutwein , L. Weise (1984): Hydrogeochemical investigations on Erzgebirge pits and surface waters. In: Geochimica et Cosmochimica Acta , Volume 26, pp. 1333-1348.
- ^ Fritz Schlegel, Klaus Schumann, Jürgen Siemroth (1992): Findings of heaps of secondary bismuth minerals from Schneeberg in the Ore Mountains. In: Lapis , Volume 25 (2), pp. 13-33.
- ^ Albin Weisbach : Mineralogical notes: 6. Pucherite . In: New Yearbook for Mineralogy, Geology and Palaeontology . 1880 II. Schweizerbart, Stuttgart 1880, p. 113 .
- ↑ Mindat - Number of localities for Pucherit
- ↑ Find location list for Pucherite at the Mineralienatlas and at Mindat