Nadorite

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Nadorite
Nadorite-177581.jpg
Group of tabular nadorite crystals from Djebel Debar, Constantine Province , Algeria (size: 4.7 cm × 2.9 cm × 2.7 cm)
General and classification
other names

Ochrolite

chemical formula PbSbO 2 Cl
Mineral class
(and possibly department) 		Halides
System no. to Strunz
and to Dana 		3.DC.30 ( 8th edition : III / D.10)
02/10/05/02
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol orthorhombic-dipyramidal; 2 / m  2 / m  2 / m
Space group Cmcm (No. 63)Template: room group / 63
Lattice parameters a  = 5.603 (5)  Å ; b  = 12.245 (8) Å; c  = 5.448 (7) Å
Formula units Z  = 4
Twinning after (101)
Physical Properties
Mohs hardness 3.5 to 4
Density (g / cm 3 ) measured: 7.02; calculated: 7.06
Cleavage completely after {010}
colour smoky brown, brownish yellow to yellow
Line color yellow to yellowish white
transparency translucent
shine Resin gloss to diamond gloss
Crystal optics
Refractive indices n α  = 2.300
n β  = 2.340 to 2.350
n γ  = 2.360 to 2.400
Birefringence δ = 0.060 to 0.100
Axis angle 2V = 85 ° (measured); 88 ° (calculated)

Nadorite (also Ochrolite ) is a rarely occurring mineral from the mineral class of " halides ". It crystallizes in the orthorhombic crystal system with the chemical composition PbSbO 2 Cl, so chemically speaking it is a lead - antimony oxyhalide with chlorine .

Nadorite usually develops tabular or pseudo-cubic or pseudo-octahedral crystals with a resin-like to diamond-like sheen on the surfaces, but also occurs in the form of roughly radial, concentric masses. The crystals are translucent and have a smoky brown or yellow to brownish-yellow color. The mineral leaves a yellow to yellowish-white line on the marking board .

Etymology and history

Nadorite was first discovered in the mine "Nador n'Bails" (French Mine du Nador N'Baïls ) on Mount Djebel Nador in the Algerian province of Constantine and described in 1870 by Theodore Flajolot , who named the mineral after its type of locality .

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the nadorite belonged to the mineral class of the "halides" and there to the department of the "oxyhalides", where together with mendipite it forms the "mendipite-nadorite group" with the system -No. III / D.10 and the other members asisite , Blixit , Damarait , Ekdemit , Heliophyllit , Kombatit , Mereheadit , Parkinsonit , Penfieldit , Perit , Philolithit , Pinalit , Sahlinit , Schwartzembergit , Seeligerit , Sundiusit , Symesit and Thorikosit formed.

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), classifies nadorite in the expanded division of "oxyhalides, hydroxyhalides and related double halides". This is, however, further subdivided according to the predominant metals in the compound, so that the mineral can be found according to its composition in the sub-section "With Pb (As, Sb, Bi) without Cu", where it is only found together with Perite after it named "Nadoritgruppe" with the system no. 3.DC.30 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns nadorite to the “halides” class and there to the “oxyhalides and hydroxyhalides”. Here it is together with Perit in the " Perit series " with the system no. 02/10/05 to be found in the subsection " Oxyhalides and hydroxyhalides with the formula A (O, OH) X q ".

Crystal structure

Nadorite crystallizes orthorhombically in the space group Cmcm (space group no. 63) with the lattice parameters a  = 5.603 (5)  Å ; b  = 12.245 (8) Å and c  = 5.448 (7) Å and 4 formula units per unit cell . Template: room group / 63

Education and Locations

Strong yellow nadorite crystal from Långban , Värmland, Sweden (image width: 1.3 mm)

Nadorite is formed metasomatically as a conversion product from other minerals in the oxidation zone of hydrothermally formed antimony deposits . As accompanying minerals may include Anglesite , Bindheimite , Cerussite , galena , Jamesonit , Mimetite , Senarmontit , Smithsonite , sphalerite and Valentinit occur.

As a rare mineral formation, Nadorite could only be detected at a few sites, with around 15 sites known to date (as of 2014). Its type locality "Nador n'Bails" ( Mine du Nador N'Baïls ) on Djebel Nador is the only known site in Algeria to date.

In Germany, the mineral has so far only been discovered in the “Reichensteinerberg” mine near Reichenstein (Puderbach) in Rhineland-Palatinate, and the only site in Austria so far is a slag dump near the village of Waitschach in Carinthia.

Other previously known sites include Broken Hill in the Australian state of New South Wales, the Madjarovo deposit in the Rhodope Mountains in the Bulgarian Oblast Chaskowo, the Tsumeb Mine in Namibia, the Långban mining community and the Harstigen Mine near Pajsberg in the Swedish municipality of Filipstad ( Värmland), some pits in the English county of Cornwall and the Crestmore quarries in Riverside County of the US state California.

See also

literature

  • T. Flajolot: Note sur des combinaisons cristallisées d'oxyde de plomb et d'oxyde d 'antimoine, d'oxyde de plomb el d'acide antimonique, de la province de Constantine (Algérie) . In: Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences . tape 71 , 1870, p. 237–239 ( rruff.info [PDF; 145 kB ; accessed on May 10, 2017]).
  • Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 495 (first edition: 1891).
  • Helmut Schrätze , Karl-Ludwig Weiner : Mineralogy. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 339 .
  • Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p. 370 .

Web links

Commons : Nadorite  - collection of images, videos and audio files

Individual evidence

  1. ^ A b 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.  177 .
  2. ↑ a b c d G. Giuseppetti, C. Tadini: Riesame della struttura cristallina della nadorite: PbSbO 2 Cl . In: Periodico di Mineralogia . tape 42 , 1973, pp. 335–345 ( rruff.info [PDF; 584 kB ; accessed on July 28, 2017]).
  3. ↑ a b Nadorite . 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; 67  kB ; accessed on May 10, 2017]).
  4. ↑ a b c d e Mindat - Nadorite
  5. ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp.  495 (first edition: 1891).
  6. ↑ Directeurs et anciens professeurs de l'Ecole des mines de Saint-Etienne
  7. ↑ Mindat - Number of localities for Nadorite
  8. ↑ Find location list for nadorite in the Mineralienatlas and Mindat