O'Danielit

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O'Danielit
General and classification
other names
  • Odanielite
  • IMA 1979-040
chemical formula
  • NaZn 3 (AsO 4 ) (AsO 3 OH) 2
  • NaZn 3 [(AsO 3 OH) 2 | AsO 4 ]
  • NaZn 3 H 2 (AsO 4 ) 3
  • Na (Zn, Mg) 3 H 2 (AsO 4 ) 3
  • H 2 Na (Zn, Mg) 3 (AsO 4 ) 3
  • H 2 NaZn 3 (AsO 4 ) 3
Mineral class
(and possibly department) 		Phosphates, arsenates, vanadates
System no. to Strunz
and to Dana 		8.AC.10 ( 8th edition : VII / A.07)
02.38.03.07
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group C 2 / c (No. 15)Template: room group / 15
Lattice parameters a  = 12.113  Å ; b  = 12.445 Å; c  = 6.793 Å
β  = 112.87 °
Formula units Z  = 4
Physical Properties
Mohs hardness ≈ 3
Density (g / cm 3 ) > 4.24 (measured); 4.49 (calculated)
Cleavage very perfect after {010} and {100}, indicated after {001}
Break ; Tenacity uneven; brittle
colour pale purple
Line color White
transparency transparent
shine Glass gloss
Crystal optics
Refractive indices n α  = 1.745
n β  = 1.753
n γ  = 1.778
Birefringence δ = 0.033
Optical character biaxial positive
Axis angle 2V = ≈ 60 ° (measured); 2V = 60 ° (calculated)
Pleochroism not pleochroic
Other properties
Chemical behavior soluble in HCl and HNO 3

O'Danielite is a very rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the monoclinic crystal system with the chemical composition NaZn 3 (AsO 4 ) (AsO 3 OH) 2 and is therefore chemically a sodium - zinc - arsenate with two additional protonated arsenate groups.

O'Danielit only develops ingrown granular aggregates at its type locality , which can be elongated in two different directions and then grown together radially. Typical is the association with cuproadamin , prosperite and coritnigite in a matrix of chalcosine and tennantite .

The type locality of the mineral is the Tsumeb Mine near Tsumeb , Oshikoto Region , Namibia .

Etymology and history

The discoverer of the O'Danielite is Bruno H. Geier (1902–1987), the former chief mineralogist of the Tsumeb Corporation , who found the mineral in a place in the Tsumeb Mine that is no longer comprehensible today. The collector Wolfgang Bartelke was able to acquire material from this find and showed the strikingly colored mineral to Paul Keller, Professor of Mineralogy and Crystallography at the University of Stuttgart . Keller and his colleagues carried out the tests necessary for characterization as a new mineral and presented the results to the International Mineralogical Association (IMA), which recognized it in 1979. In 1981 a German-American team of scientists led by Paul Keller , Heinz Hess, Pete J. Dunn and Dale E. Newbury published it in the German science magazine "New Yearbook for Mineralogy, MONTHLY" as O'Danielit ( English O'Danielite ) described. The authors named the mineral after the professor for mineralogy at the Johann Wolfgang Goethe University Frankfurt am Main Herbert O'Daniel (1903-1977), former editor of the "New Yearbook for Mineralogy" and the "Zentralblatt für Mineralogie". O'Daniel played a key role in the reconstruction of the German Mineralogical Society (DMG) and served as its chairman from 1948 to 1950.

The type of material for O'Danielit (holotype) is at the University of Stuttgart (location TM 79.40-8701.13 / 0/824-s27 / 2) and the Smithsonian Institution belonging to National Museum of Natural History , Washington, DC (catalog no. 145966), kept.

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the O'Danielite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the division of "anhydrous phosphates [PO 4 ] 3− , without foreign anions" , where he formed the unnamed group VII / A.07 together with Bradaczekit , Johillerit , Nickenichit and Yazganit .

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the IMA, also assigns O'Danielite to the class of "phosphates, arsenates and vanadates" and there to the category of "phosphates, etc. without additional anions; without H 2 O “. However, this section is even more precisely subdivided according to the size of the cations involved , so that the mineral can be found according to its composition with the cations sodium and magnesium in the sub-section “With medium-sized and large cations”, where it can be found together with Alluaudit , Arseniopleit , Bradaczekit , Groatit (IMA 2008-054), Karyinit , Ferroalluaudit , Ferrohagendorfit , Hagendorfit , Johillerit, Maghagendorfit , Manitobait (IMA 2008-064), Nickenichit, Varulith and Yazganit the Hagendorfitgruppe with the system number. 8.AC.10 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the O'Danielite to the class of "phosphates, arsenates and vanadates" and there in the department of "anhydrous phosphates etc.". Here he is in the " Alluaudit subgroup within the Alluaudit-Wyllieit group " with the system no. 38.02.03 and the other members Alluaudit, Ferroalluaudit, Ferrohagendorfit, Groatit, Hagendorfit, Johillerit, Maghagendorfit, Manitobait, Nickenichit, Varulite and Yazganit within the sub-section " Anhydrous phosphates etc., (A + B 2+ ) 3 (XO 4 ) 2 " to find.

Chemism

Microprobe analyzes on O'Danielite from the Tsumeb Mine showed mean values ​​of 4.7% Na 2 O; 2.9% MgO; 0.3% CaO; 0.6% MnO; 0.2% FeO; 33.8% ZnO; 54.4% As 2 O 3 and 2.8% H 2 O, from which, based on 12 oxygen atoms, the empirical formula H 1.96 (Na 0.95 Ca 0.03 ) Σ = 0.98 (Zn 2 , 60 Mg 0.45 Mn 0.05 Fe 0.02 ) Σ = 3.12 (As 0.99 O 4 ) 3 , which results in H 2 NaZn 3 (AsO 4 ) 3 (or NaZn 3 (AsO 4 ) (AsO 3 OH) 2 in the notation with protonated arsenate groups) can be idealized. This ideal formula requires Na 2 O contents of 4.86% in the O'Danielite ; 38.27% ZnO; 54.05% As 2 O 3 and 2.82% H 2 O.

O'Danielit represents the Zn 2+ -dominant analogue of a previously only synthetically known Mg 2+ -dominated end member (Na-Mg-arsenate-hydroxyarsenate) of a possibly complete mixed crystal series. It is also the Zn-dominant analogue of Mn- dominated canutite and MnMg 2 -dominated magnesiocanutite .

Crystal structure

O'Danielite crystallizes in the monoclinic crystal system in the space group C 2 / c (space group no. 15) with the lattice parameters a  = 12.113  Å ; b  = 12.445 Å; c  = 6.793 Å and β = 112.87 ° as well as four formula units per unit cell . The lattice parameters found by Tamara Ðorðević and co-workers on a synthetic analogue of O'Danielite (hydrothermal synthesis) are a  = 12.023  Å ; b  = 12.385 Å; c  = 6.750 Å and β = 112.79 °. Template: room group / 15

The crystal structure of the synthetic analogue of O'Danielite is based on ZnO 4 (OH) 2 - and ZnO 6 - octahedra with common edges that form chains parallel (101) and are connected by [AsO 4 ] - tetrahedra . The chains form two types of channels in parallel [001]. While the H atoms of the (OH) groups are located in the channels of the first type, the Na atoms are located in the channels of the second type.

O'Danielite is isotypic (isostructural) to the protonated representatives of the Alluaudit upper group.

properties

morphology

O'Danielit only develops ingrown, xenomorphic , granular aggregates up to 3 × 1 × 0.5 mm in size, some of which are flat-tabular after the anterior pinacoid {100} or stretched along the c-axis [001] . In general, the grains are then grown together to form radially radial aggregates.

physical and chemical properties

The crystals of O'Danielite are very typically pale violet in color, but their streak color is always white. The surfaces of the transparent crystals have a glass-like sheen , which agrees well with the values ​​for light refraction .  Medium to high values ​​for light refraction (n α  = 1.745; n β  = 1.753; n γ = 1.778) and for birefringence (δ = 0.033) were found on the crystals of O'Danielite . O'Danielit is not pleochroic .

O'Danielit has two very perfect cleavages according to {010} and {100} and an indicated cleavage according to {001}. Due to its brittleness , however , it breaks like amblygonite , with the fracture surfaces being uneven. With a Mohs hardness of ≈ 3, the mineral is one of the medium-hard minerals and, like the reference mineral calcite, can be scratched with a copper coin. The O'Danielite grains sink in Clerici solution , so their measured density is> 4.24 g / cm³. The calculated density for the mineral is 4.49 g / cm³. O'Danielit is neither in the long term nor in the short wavelength UV light , a fluorescent .

O'Danielit is soluble in hydrochloric acid (HCl) and nitric acid (HNO 3 ).

Education and Locations

As an extremely rare mineral formation, O'Danielite could only be described from one site so far (as of 2018). The type locality is the "Tsumeb Mine" near Tsumeb, Oshikoto region , Namibia , although the exact location within the mine is unknown. However, it was very likely in the area of ​​the 2nd oxidation zone . Occurrences of O'Danielite in Germany , Austria or Switzerland are therefore not known.

O'Danielit is a typical secondary mineral , which is in the oxidation zone an arsenic-rich polymetallic non-ferrous metal - deposit has formed. The zinc comes from the weathering of sphalerite and the arsenic from the oxidized tennantite. The sodium will have been loosened from the host rock .

In the "Tsumeb Mine" the mineral was found on a par with corroded copper ores, mainly consisting of tennantite and chalcosine. Paragenesis minerals are green konichalcite , green cuproadamin , brilliant, colorless, water-clear, needle-like prosperite crystals and pale pink - colored coritnigite containing manganese . The succession (formation sequence) is indicated with Konichalcit → Cuproadamin → O'Danielit → Prosperit → Koritnigit. Other accompanying minerals are stranskiite , lavendulan , köttigite and tsumcorite .

use

With a theoretical ZnO content of approx. 38% by weight, O'Danielite would be a rich zinc ore . However, due to its rarity, it is only of interest to mineral collectors.

See also

literature

  • Paul Keller, Heinz Hess, Pete J. Dunn, Dale E. Newbury: O ʼ Danielit, NaZn 3 H 2 (AsO 4 ) 3 , a new mineral from Tsumeb, Namibia . In: New yearbook for mineralogy, monthly books . tape 1981 , no. 4 , 1981, p. 155-160 .
  • O'danielite . 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; 64 kB ; accessed on June 16, 2018]).

Web links

Individual evidence

  1. ↑ Webmineral - Odanielite (O'Danielite) (English)
  2. ↑ a b c d e f g Tamara Đorđević, Astrid Wittwer, Sergey V. Krivovichev: Three new alluaudite-like protonated arsenates: NaMg 3 (AsO 4 ) (AsO 3 OH) 2 , NaZn 3 (AsO 4 ) (AsO 3 OH ) 2 and Na (Na 0.6 Zn 0.4 ) Zn 2 (H 0.6 AsO 4 ) (AsO 3 OH) 2 . In: European Journal of Mineralogy . tape 27 , no. 4 , 2015, p. 559-573 , doi : 10.1127 / 0935-1221 / 2004 / 0016-0353 .
  3. ^ Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  430 .
  4. ↑ 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 Paul Keller, Heinz Hess, Pete J. Dunn , Dale E. Newbury: O ʼ Danielit, NaZn 3 H 2 (AsO 4 ) 3 , a new mineral from Tsumeb, Namibia . In: New yearbook for mineralogy, monthly books . tape 1981 , no. 4 , 1981, p. 155-160 .
  5. ↑ a b c d e f g h Mindat - O'Danielite (English)
  6. ↑ a b c O'danielite . 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; 64  kB ; accessed on June 16, 2018]).
  7. ^ IMA / CNMNC List of Mineral Names; March 2018 (PDF 1.65 MB)
  8. ↑ a b Paul Keller, Heinz Hess: The crystal structures of O ʼ Danielit, Na (Zn, Mg) 3 H 2 (AsO 4 ) 3 and Johillerite, Na (Mg, Zn) 3 Cu (AsO 4 ) 3 . In: New yearbook for mineralogy, monthly books . tape 1988 , no. 5 , 1981, pp. 395-404 .
  9. ^ A b Paul Keller: Tsumeb . In: Lapis . tape 9 , no. 7/8 , 1984, pp. 48 .
  10. ↑ a b Georg Gebhard: Tsumeb . 1st edition. GG Publishing, Grossenseifen 1999, ISBN 3-925322-03-5 , pp. 256 .
  11. ^ German biography - Herbert O'Daniel
  12. ↑ Typmineral catalog Germany - storage of the type material for O'Danielit
  13. ↑ Mindat - Number of localities for O'Danielit
  14. ↑ a b List of locations for O'Danielite in the Mineralienatlas and in Mindat
  15. ↑ Tsumeb.com - O'Danielite (English)
  16. ↑ Paul Keller, Wolfgang Bartelke: TSUMEB! new minerals and their associations . In: Mineralogical Record . tape 13 , no. 3 , 1982, pp. 142 .