Hydrokenoelsmoreit
| Hydrokenoelsmoreit | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | □ 2 W 2 O 6 (H 2 O) |
|
Mineral class (and possibly department) |
Oxides and hydroxides |
| System no. according to Strunz | 4.DH.15 ( 8th edition : IV / E.02) |
| Crystallographic Data | |
| Crystal system | cubic |
| Crystal class ; symbol | cubic hexakisoctahedral; 4 / m 3 2 / m |
| Space group | Fd 3 m (No. 227) |
| Lattice parameters | a = 10.203 Å |
| Formula units | Z = 16 |
| Frequent crystal faces | {111} |
| Twinning | according to {111}, spinel law |
| Physical Properties | |
| Mohs hardness | 3 |
| Density (g / cm 3 ) | 6.025 (calculated) |
| Cleavage | no |
| Break ; Tenacity | splintery; brittle |
| colour | colorless, white, yellow, orange, pale brown, black |
| Line color | White |
| transparency | translucent |
| shine | Diamond luster |
| Crystal optics | |
| Refractive index | n = 2.24 ± 0.005 |
| Pleochroism | optically isotropic |
| Other properties | |
| Chemical behavior | Decomposition by acids with formation of yellow tungsten oxide |
Hydrokenoelsmoreit is a rarely occurring mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the cubic crystal system with the idealized chemical composition □ 2 W 2 O 6 (H 2 O). □ represents a blank space (vacancy) in the corresponding position. Hydrokenoelsmoreit only develops tiny, octahedral crystals with a diamond-like sheen , which are colorless, white or yellowish in color. Iron-rich varieties show orange, pale brown, or black hues. Microcrystalline, powdery aggregates are much more common .
Etymology and history
The mineral turn of the century in which it was discovered tin - deposit Elsmore near the eponymous town in the New England region in the Australian state of New South Wales . Recognition by the International Mineralogical Association (IMA) took place in 2003. In 2005 it was described under the name Elsmoreit by an Australian research team led by Peter A. Williams , Peter Leverett , James L. Sharpe , Davis M. Colchester and John Rankin . The name of the mineral refers to the place where it was first found.
After the redefinition of the nomenclature of the pyrochlore supergroup with the general composition A 2 B 2 X 6 Y, the mineral now counts as a member of the newly created Elsmoreit group with dominant H 2 O due to its chemical composition and the dominance of tungsten in the B position on the anion side. The new name Hydrokenoelsmoreit refers to the membership of the Elsmoreit group, the dominance of water on the Y-position and the vacancy (blank) on the A-position.
Type material of the mineral is in the collection of the oldest natural history museum in the world, the Australian Museum in Sydney , New South Wales, Australia (reg.no. D53020).
classification
The current classification of the International Mineralogical Association (IMA) counts the hydrokenoelsmoreite to the pyrochlore upper group with the general formula A 2– m B 2 X 6– w Y 1– n , in which A , B , X and Y different positions in the structure the minerals of the pyrochlore upper group with A = Na, Ca, Sr, Pb 2+ , Sn 2+ , Sb 3+ , Y, U, □, or H 2 O; B = Ta, Nb, Ti, Sb 5+ or W; X = O, OH or F and Y = OH - , F, O, □, H 2 O or very large (>> 1.0 Å) monovalent cations such as K, Cs or Rb. To pyrochlore supergroup include not only Hydrokenoelsmoreit still Fluorcalciomikrolith , Fluornatromikrolith , Hydrokenomikrolith , Hydroxycalciomikrolith , Hydroxykenomikrolith , Kenoplumbomikrolith , Oxynatromikrolith , Oxystannomikrolith , Oxystibiomikrolith , Cesiokenopyrochlor , Fluorcalciopyrochlor , Fluornatropyrochlor , Hydrokenopyrochlor , Hydropyrochlor , Hydroxycalciopyrochlor , Hydroxykenopyrochlor , Hydroxymanganopyrochlor , Hydroxynatropyrochlor , Oxycalciopyrochlor , Fluorcalcioroméit , Hydroxycalcioroméit , Hydroxyferroroméit , Oxycalcioroméit , Oxyplumboroméite , Hydroxykenoelsmoreit , Fluornatrocoulsellit and Hydrokenoralstonit . Hydrokenoelsmoreit forms together with Hydroxykenoelsmoreit within the pyrochlore upper group the Elsmoreit group .
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the (Hydrokeno) elsmoreit belonged to the general section of "Oxides with a metal: oxygen ratio = 2: 3 (M 2 O 3 and related compounds)", where it belongs together with Anthoinit, Cerotungstit- (Ce), Hydrotungstit, Meymacit, Mpororoit, Tungstit, Yttrotungstit- (Y) the "unnamed group" with the system no. IV / E.02 .
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 Hydrokenoelsmoreit to the category of "Oxides with the molar ratio of metal: oxygen = 1: 2 and comparable". However, this section is further subdivided according to the relative size of the cations involved and the crystal structure, so that the mineral according to its composition and structure is classified in the sub-section “With large (± medium-sized) cations; Layers of edge-linked octahedra ”can be found, where it forms the pyrochlore supergroup 4.DH.15 together with all representatives of the pyrochlore, microlith, betafit, Roméit and Elsmoreit groups . Hydrokenoelsmoreit (formerly Elsmoreit, Ferritungstit and Alumotungstit) is the only representative of the Elsmoreit Group.
Hydrokenoelsmoreit is not yet included in the systematics of minerals according to Dana , which is mainly used in the English-speaking area , and the Elsmoreit group is also missing.
Crystal structure
Hydrokenoelsmoreit crystallizes in the cubic crystal system in the space group Fd 3 m (space group no. 227) , with the lattice parameter a = 10.203 Å and sixteen formula units per unit cell .
properties
morphology
Hydrokenoelsmoreit forms tiny crystals with the octahedron {111} as the shape defining the costume, which can be twinned according to {111} (spinel law). Microcrystalline to powdery aggregates are more common. Alumotungstit as a variety of Hydrokenoelsmoreit is known in perfect octahedral crystals up to 0.25 mm in size.
physical and chemical properties
The color of the crystals and aggregates of the Hydrokenoelsmoreits is colorless to white, the line color of the translucent mineral, on the other hand, is always white. The Hydrokenoelsmoreit crystal have a diamond-like sheen . The mineral shows no cleavage and , due to its brittleness, breaks like chrysotile , with the fracture surfaces being splintery. With a Mohs hardness of 3, Hydrokenoelsmoreit is one of the medium-hard minerals whose hardness corresponds to the reference mineral calcite . The calculated density of the mineral is a maximum of 6.025 g / cm³. Due to the extremely small crystals, the properties of the Elsmoreits were determined in the type publication on synthetic material.
The Ferritungstit variety is orange, yellow to pale brown, the Alumotungstit variety is white to pale yellow. V- and Cr-rich varieties from the Clara mine in the Black Forest are colored black.
Hydrokenoelsmoreit is decomposed by acids with the formation of yellow tungsten oxide.
Modifications and varieties
After the redefinition of the nomenclature of the pyrochlore supergroup, three previously independent minerals are grouped under “Hydrokenoelsmoreit”. The former Elsmoreit type is now the Hydrokenomicrolite type, the two formerly independent minerals Ferritungstit and Alumotungstit now form varieties. Ferritungstit is an Fe-containing variety with W> Fe, Alumotungstit an Al-containing variety with W> Al. In addition, V- and Cr-rich varieties are known from the Clara mine in the Black Forest.
The inadequately characterized Jixianite could represent the lead- dominant analogue to Hydrokenoelsmoreit and would then be called "Plumboelsmoreit". However, since there are no crystal structure investigations, it is not possible to determine the dominant anion on the Y position of the jixianite; his position in the Elsmoreit group remains unclear.
Education and Locations
Hydrokenoelsmoreit formed at the type locality through oxidation of ferberite in the oxidation zone of weakly weathered, Sn-, W-, Mo- and Bi-mineralized granite pegmatitic veins , which are associated with pegmatitic old veins in a stick-shaped granite . Quartz , light mica , cassiterite , arsenopyrite , native bismuth , chalcopyrite , ferberite and molybdenite were identified as accompanying minerals .
As a rather rare mineral formation, Hydrokenoelsmoreit can sometimes be abundant at various sites, but overall it is not very widespread. So far (as of 2016) around one hundred sites are known, but mostly the varieties Ferritungstit and Alumotungstit have been identified. About 10 locations are known for the pure formula Hydrokenoelsmoreit.
In addition to its type locality, the Elsmore tin deposit in the New England region, New South Wales, the mineral was obtained from Australia, among others, from the Wolfram Wonder Mines, Wellesley Co., New South Wales, and from the Wolfram Mine, Pittong, Victoria (Australia) , described. Locations in Europe are the Clara mine in the Rankach Valley near Oberwolfach , Black Forest , (Baden-Württemberg), Germany , the Hingston Down Quarry, Gunnislake, Calstock , Callington District , Cornwall , and the Drakelands Mine, Plympton near Tavistock in Devon , both England , United Kingdom , the “La Grange Mine” near Meymac , Corrèze department , and “La Bertrande” near Saint-Sulpice-Laurière , Haute-Vienne department , both Nouvelle-Aquitaine , France , the “Borralha Mine” near Salto , Montalegre , Vila Real district , and the "Fonte Santa Mine", Lagoaça , Freixo de Espada à Cinta , Bragança district , both Portugal and from the "Miniera di Alpe Machetto", Cascine Machetto, Quittengo , Valle del Cervo, Biella province and from the north slope the Pizzo Ragno on the Alpe Campra near Druogno , Valle Vigezzo , Province Verbano-Cusio-Ossola , both Piedmont and the "Miniera Santa Lucia" near Fluminimaggiore , Province Carbonia-Iglesias , and the "Miniera di Fenugu Sibiri" near Gonnos fanadiga , province of Medio Campidano , both Sardinia , Italy . Locations in Austria and Switzerland are not known.
In Africa from the “Gifurwe Mines” in the Gifurwe sector, Cyeru, Northern Province , Rwanda , as well as from the “Kirwa Mine”, the “Nyamulilo Mine” and the “Mpororo” tungsten deposit near Kisoro , all in the Kigezi District , Uganda .
In Asia from the “Akchatau” and “Kara-Oba” deposits in the Betpakdala Desert, both Qaraghandy Province , Kazakhstan , from the “Kramat Pulai Mine” near Kramat Pulai, Kinta , Perak , Malaysia , the “Nitta Mine” (Hayasaki mine) on the south-west of Kyushu lying Nansei Islands belonging island of Yakushima , Kagoshima Prefecture , and the "Ofuku mine" in the town of mine , Yamaguchi Prefecture region Chūgoku , Honshu , all Japan .
From “Flo Property” in the Mayo Mining District near Mayo in the Kalzas Mountains, Yukon , Canada . In the United States , from the Eureka Mine in the Tungsten District, Boulder County , Colorado , the Mountain King Mine, Potosi District, Osgood Mts, Humboldt Co. , and the Luning Area, Mineral Co. , both Nevada , the "Gold Hill District" in Deep Creek Mts., Tooele County , Utah , and the "Germania Mine" on Adams Mountain, Huckleberry Range, Stevens Co. , Washington . Also from the Farallon Mine in Cerro Tazna , Atocha Quechisla District, Nor Chichas Province , Potosí Department , Bolivia and the “La Bismutina Mine”, Minas Department , Córdoba , and from the “Cerro Liquinaste” near Tusaquillas, Cochinoca Department , Jujuy Province , both Argentina .
use
Hydrokenoelsmoreit is economically insignificant due to its rarity and is only a coveted mineral for the collector.
See also
literature
- Peter A. Williams, Peter Leverett, James L. Sharpe, Davis M. Colchester, John Rankin (2005): Elsmoreite, cubic WO 3 • 0.5H 2 O, a new mineral species from Elsmore, New South Wales, Australia. In: Canadian Mineralogist , Volume 43, pp. 1061-106 ( PDF, 106 kB ).
- Elsmoreite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF, 200 kB ).
Web links
- Mineral Atlas: Hydrokenoelsmoreit (Wiki)
- Mindat - Hydrokenoelsmoreite
- Webmineral - Hydrokenoelsmoreite
- American-Mineralogist-Crystal-Structure-Database - Hydrokenoelsmoreite
Individual evidence
- ↑ a b c d Daniel Atencio, Marcelo B. Andrade, Andrew G. Christy, Reto Gieré, Pavel M. Kartashov: The Pyrochlore supergroup of minerals: Nomenclature . In: The Canadian Mineralogist . tape 48 , 2010, p. 673–698 , doi : 10.3749 / canmin.48.3.673 (English, rruff.info [PDF; 1,4 MB ; accessed on August 30, 2018]).
- ^ Andy G. Christy, Daniel Atencio (2013): Clarification of status of species in the pyrochlore supergroup. In: Mineralogical Magazine , Volume 77, pp. 13-20 ( PDF, 85 kB ).
- ↑ a b c d e f g Peter A. Williams, Peter Leverett, James L. Sharpe, Davis M. Colchester, John Rankin (2005): Elsmoreite, cubic WO 3 • 0.5H 2 O, a new mineral species from Elsmore, New South Wales, Australia. In: Canadian Mineralogist , Volume 43, pp. 1061-106 ( PDF, 106 kB ).
- ↑ a b Mindat - Hydrokenoelsmoreite
- ↑ Elsmoreite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF, 200 kB ).
- ^ A b Jan H. Bernard, Jaroslav Hyršl: Minerals and their localities . 1st edition. Granit, Praha 2004, ISBN 80-7296-039-3 , p. 28 and 213 .
- ↑ Mindat - Number of localities for Hydrokenoelsmoreit
- ↑ a b List of sites for Hydrokenoelsmoreit in the Mineralienatlas and in Mindat