Yancowinnait
| Yancowinnait | |
|---|---|
| General and classification | |
| other names |
IMA 2010-030 |
| chemical formula | PbCuAl (AsO 4 ) 2 (OH, H 2 O) |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.CG.20 ( 8th edition : VII / C.31) 02.33.02.04 |
| Similar minerals | Gartrellit |
| Crystallographic Data | |
| Crystal system | triclinic |
| Crystal class ; symbol | triclinic pinacoidal; 1 |
| Space group | P 1 (No. 2) |
| Lattice parameters |
a = 5.444 Å ; b = 5.640 Å; c = 7.518 Å, α = 67.89 °; β = 69.48 °; γ = 70.18 ° |
| Formula units | Z = 1 |
| Physical Properties | |
| Mohs hardness | ≈3 |
| Density (g / cm 3 ) | > 3.8 (measured); 5.17 (calculated) |
| Cleavage | very perfectly parallel {111} |
| colour | yellowish green to green |
| Line color | yellow |
| transparency | translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.963 n γ = 1.906 |
| Refractive index | n = 1.896 |
| Birefringence | δ = 0.057 |
| Optical character | biaxial positive (analogous to Gartrellit) |
| Pleochroism | weakly from X = pale yellow (almost colorless) through Y = yellow to Z = pale orange |
Yancowinnaite is a very rare mineral from the mineral class of " phosphates , arsenates and vanadates " with the chemical composition PbCuAl (AsO 4 ) 2 (OH, H 2 O). From a chemical point of view, it is therefore a water-containing lead - copper - aluminum phosphate with a variable proportion of additional hydroxide ions .
Yancowinnaite is almost cryptocrystalline at its type locality and develops tabular crystallites with a size of less than 10 μm, which come together up to 5 mm in size, rosette-shaped aggregates and form coatings on gartrellite . The type locality of the mineral is the “Kintore Opencut” open-cast mine near Broken Hill in Yancowinna County, New South Wales , Australia , in which lead- zinc has been used by the mining company “Normandy Mining” from the late 1980s to 1996 and later by “Newmont Mining” - ores have been mined.
Etymology and history
In 1988, several specimens with various representatives of the tsumcorite group were recovered from ore stockpiles of the Kintore Opencut in Broken Hill, Australia , two of which were found to be a mineral identified as new. After intensive research by an Australian team of mineralogists and crystallographers led by Peter Elliott and Allan Pring , the new mineral was presented to the International Mineralogical Association (IMA), which recognized it as a new mineral in July 2010. The first description as Yancowinnait was in 2015 by Elliott and Pring in the Australian science magazine "Australian Journal of Mineralogy". The authors named the mineral after its location in Yancowinna County, the term "Yancowinna" probably coming from a local Aboriginal expression .
The type material for Yancowinnait is stored under catalog number G33029 in the collection of the South Australian Museum in Adelaide , South Australia in Australia.
classification
The current classification of the International Mineralogical Association (IMA) counts the Yancowinnaite to the tsumcorite group with the general formula Me (1) Me (2) 2 (XO 4 ) 2 (OH, H 2 O) 2 , in which Me (1), Me (2) and X different positions in the structure of the minerals of the tsumcorite group with Me (1) = Pb 2+ , Ca 2+ , Na + , K + and Bi 3+ ; Me (2) = Fe 3+ , Mn 3+ , Cu 2+ , Zn 2+ , Co 2+ , Ni 2+ , Mg 2+ and Al 3+ and X = As 5+ , P 5+ , V 5+ and represent S 6+ . To Tsumcoritgruppe include not only Yancowinnait still Cabalzarit , Cobaltlotharmeyerit , Cobalttsumcorit , Ferrilotharmeyerit , Gartrellit , Helmutwinklerit , Kaliochalcit , Krettnichit , Lotharmeyerit , Lukrahnit , Manganlotharmeyerit , Mawbyit , Mounanait , Natrochalcit , Nickellotharmeyerit , Nickelschneebergit , Nickeltsumcorit , Phosphogartrellit , Rappoldit , Schneebergit , Thometzekit , Tsumcorit and Zinc Gartrellite .
The 8th edition of the mineral classification according to Strunz , which is now outdated but still in use , does not yet list the Yancowinnait. He would, together with Cabalzarit , Cobaltlotharmeyerit , Cobalttsumcorit , Ferrilotharmeyerit , Gartrellit , Helmutwinklerit , Krettnichit , Lotharmeyerit , Lukrahnit , Manganlotharmeyerit , Mawbyit , Mounanait , Nickellotharmeyerit , Nickelschneebergit , Phosphogartrellit , Rappoldit , Schneebergit , Thometzekit , Tsumcorit and Zinkgartrellit for "Tsumcorit-Gartrellit Group “With the system no. VII / C.31 in the mineral class of "phosphates, arsenates and vanadates" and there to be counted in the division of "water-containing phosphates without foreign anions ".
The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), does not yet know the Yancowinnait. Here, too, it would be placed in the “Phosphates, etc.” section without additional anions; with H 2 O “. However, this is further subdivided according to the relative size of the cations involved and the molar ratio of phosphate, arsenate or vanadate complex to the water of crystallization content , so that the mineral can be classified according to its composition in the subsection “With large and medium-sized cations; RO 4 : H 2 O = 1: 1 ”would be found where, together with the other members gartrellite, helmutwinklerite, lukrahnite, phosphogartrellite, rappoldite and zinc gartrellite, the“ helmutwinklerite group ”with the system no. 8.CG.20 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , would place the Yancowinnaite in the class of "phosphates, arsenates and vanadates" and there in the department of "composite phosphates etc.". Here it would be together with Gartrellite, Lukrahnit and Zinc Gartrellite in the " Gartrellite Group " with the system no. 43.02.02 within the subsection " Compound phosphates etc., (water-containing, normally composed anions)".
Chemism
Twenty-three microprobe analyzes on Gartrellite gave mean values of 36.43% PbO; 4.08% Fe 2 O 3 ; 5.14% Al 2 O 3 ; 0.74% ZnO; 12.98% CuO; 36.25% As 2 O 5 and 4.38% H 2 O (calculated content). Out of them is calculated on the basis of 10 oxygen atoms , the empirical formula Pb 1.02 Al 0.63 Fe 3+ 0.32 Cu 1.02 Zn 0.06 (AsO 4 ) 1.98 (OH) 1.11 (H 2 O) 0.97 , which was idealized to PbCuAl 3+ (AsO 4 ) 2 (OH, H 2 O) 2 . This requires contents of 36.56% PbO, 8.35% Al 2 O 3 , 13.03% CuO, 37.64% As 2 O 5 and 4.43% H 2 O.
Yancowinnait is a representative of the tsumcorite group . The general formula for the tsumcorite group is Me (1) Me (2) 2 ( X O 4 ) 2 O (1) with Me (1) = Pb, Ca, Na, K and Bi; Me (2) = Fe, Mn, Cu, Zn, Co, Ni and Al; X = P, As, V and S as well as O (1) = H 2 O, OH and F. Mixed crystal formation takes place mainly on the Me (2) position, but less frequently on the X and Me (1) position . In Yancowinnaite the highest Al contents are associated with higher Cu and lower Zn contents, so that a coupled substitution according to the scheme Cu 2+ + Al ↔ Zn + Fe 3+ is proposed.
Yancowinnaite is the Al 3+ -dominant analogue of the Fe 3+ -dominated gartrellite, with which it forms a complete mixed crystal row . After Cabalzarit, Yancowinnaite is only the second representative of the tsumcorite group with Al 3+ in the Me (2) position.
Crystal structure
Yancowinnaite crystallizes in the triclinic crystal system in the space group P 1 (space group no. 2) with the lattice parameters a = 5.444 Å ; b = 5.640 Å; c = 7.518 Å; α = 67.89 °; β = 69.48 ° and γ = 70.18 ° as well as one formula unit per unit cell .
properties
morphology
At its type locality, Yancowinnait develops tabular crystallites of <10 µm in size, which form rosette-shaped aggregates up to 5 mm in size on gartrellite.
physical and chemical properties
Yancowinnaite crystals are yellowish green to green, their line color , however, is always yellow. They are very similar to the crystals of Gartrellite, but they are usually more yellowish in color. The surfaces of the translucent Yancowinnaite crystals have a glass-like to diamond-like sheen , according to the values for light refraction (n α = 1.963, n γ = 1.906) . Yancowinnaite from the type locality is described as “only” shiny glass, probably due to the crystal size. Under the microscope, the mineral shows a weak pleochroism in the transmitted light from X = pale yellow (almost colorless) through Y = yellow to Z = pale orange. Due to the very small crystal size and the tabular shape of the crystals, the complete optical properties of the mineral cannot yet be determined. The mean refractive index is 1.896.
The mineral possesses a very perfect cleavage , which - in analogy to Gartrellite - is assumed to be parallel {111}. With a Mohs hardness of 3, Gartrellite is one of the medium-hard minerals and, if the crystal size is the same as the reference mineral calcite , it could be scratched with a copper coin. Since yancowinnaite grains sink in the heavy liquid diluted Clerici solution , their density must be greater than the value given as 3.3 g / cm³. The calculated density for Yancowinnaite is 5.31 g / cm³ (from the empirical formula) and 5.17 g / cm³ (from the ideal formula). Yancowinnait is neither in the long term nor in the short wavelength UV light , a fluorescent .
Education and Locations
Yancowinnaite is a typical secondary mineral which is formed by weathering of primary ore minerals in the oxidation zone of ore deposits . On the type locality was formed of lead, iron, copper, zinc and arsenic-containing solutions obtained by decomposition of the primary ore minerals galena , sphalerite , chalcopyrite and arsenopyrite - Löllingit have emerged, wherein the arsenic from the decomposition of arsenopyrite and arsenic minerals Löllingite comes from. The action of acidic solutions on the adjacent rock released the aluminum necessary for mineral formation. Paragenesis minerals from the original discovery in the "Kintore Opencut" are white prismatic Mimetesitkristalle , pale-blue needle-like Agardit- (Y) crystals, tiny tabular Karminitkristalle , yellow-orange Beudantit - Segnitit -Mischkristalle and yellowish brown Chlorargyrit -Kriställchen in a matrix of goethite and garnet ( Spessartine ).
As an extremely rare mineral formation, Yancowinnaite could so far (as of 2018) only be described by its type locality . The “lead ore lens No. 3 ”in the“ Kintore Opencut ”of the famous“ Broken Hill ”deposit (Broken Hill South Mine) near the place of the same name in Yancowinna Co., New South Wales, Australia.
Locations for Yancowinnait in Germany , Austria and Switzerland are therefore unknown.
use
Due to its rarity, Yancowinnaite is a mineral that is sought after by mineral collectors, but has no other meaning.
See also
literature
- Peter Elliott, Allan Pring: Yancowinnaite, a new mineral from the Kintore open cut, Broken Hill, New South Wales . In: Australian Journal of Mineralogy . tape 17 , no. 2 , 2015, p. 73-76 .
Web links
- Mineral Atlas: Yancowinnaite (Wiki)
- Mindat - Yancowinnait (English)
Individual evidence
- ↑ a b c d e f g h i j k l m n o p q r s Peter Elliott, Allan Pring: Yancowinnaite, a new mineral from the Kintore open cut, Broken Hill, New South Wales . In: Australian Journal of Mineralogy . tape 17 , no. 2 , 2015, p. 73-76 .
- ↑ Mindat - Locality Kintore Opencut
- ↑ a b Werner Krause, Klaus Belendorff, Heinz-Jürgen Bernhardt, Catherine McCammon, Herta Effenberger, Werner Mikenda: Crystal chemistry of the tsumcorite-group minerals. New data on ferrilotharmeyerite, tsumcorite, thometzekite, mounanaite, helmutwinklerite, and a redefinition of gartrellite . In: European Journal of Mineralogy . tape 10 , 1998, pp. 179-206 , doi : 10.1127 / ejm / 10/2/0179 .
- ^ A b Peter Elliott: The crystal chemistry of gartrellite group minerals from the Kintore Opencut, Broken Hill, New South Wales. In: Crystal Chemistry of Cadmium Oxysalt and associated Minerals from Broken Hill, New South Wales (Doctoral Thesis) . 1st edition. University of Adelaide, School of Earth and Environmental Sciences, Geology and Geophysics, Adelaide 2010, p. 96–129 ( edu.au [PDF; 3.2 MB ; accessed on January 16, 2018]).
- ↑ Mindat - Number of localities for Yancowinnait
- ↑ a b c List of localities for Yancowinnaite in the Mineralienatlas and Mindat
- ↑ a b Mindat - Yancowinnait