Lavendulan

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Lavendulan
Lavendulan-112544.jpg
Rock encrustation made of microcrystalline lavendulan from the Meskani Mine, Anarak , Isfahan Province , Iran (size 3.9 cm × 3.5 cm × 2.6 cm)
General and classification
other names
  • Freirinit
  • Lavendulanite
chemical formula NaCaCu 5 [Cl | (AsO 4 ) 4 ] • 5H 2 O
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates
System no. to Strunz
and to Dana 		8.DG.05 ( 8th edition : VII / D.25)
42.09.04.02
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Room group (no.) P 2 1 / n (No. 14)
Lattice parameters a  = 10.011 (1)  Å ; b  = 19.478 (2) Å; c  = 10.056 (1) Å
β  = 90.37 (1) °
Formula units Z  = 4
Physical Properties
Mohs hardness 2.5
Density (g / cm 3 ) measured: 3.54; calculated: [3.59]
Cleavage good after {010}, clearly after {100} and {001}
Break ; Tenacity uneven; brittle
colour turquoise blue , lavender blue (blue-violet), greenish blue
Line color Light Blue
transparency translucent
shine Wax gloss to glass gloss, silk gloss in aggregate form
Crystal optics
Refractive indices n α  = 1.660
n β  = 1.715
n γ  = 1.734
Birefringence δ = 0.074
Optical character biaxial negative
Axis angle 2V = measured: 33 °; calculated: 58 °
Pleochroism visible: ω = light blue to light greenish blue; ε = blue to greenish blue

Lavendulan is a rather seldom occurring mineral from the mineral class of "phosphates, arsenates and vanadates". It crystallizes in the monoclinic crystal system with the chemical composition NaCaCu 5 [Cl | (AsO 4 ) 4 ] · 5H 2 O and is therefore chemically a water-containing sodium - calcium - copper - arsenate with additional chlorine ions.

Lavendulan is translucent and develops only millimeter-sized, tabular and flake-like crystals with a wax-like to glass-like sheen on the surfaces. It is mostly found in the form of fibrous or radial to rosette-shaped mineral aggregates and crusty coatings. Its color varies between turquoise blue (greenish blue ) and lavender blue (blue violet), but its line color is always light blue.

Etymology and history

Lavendulan was first discovered in the “Old Galilean Economy” mine near Frohnau (Annaberg-Buchholz) in the Saxon Ore Mountains and described in 1837 by August Breithaupt , who named the mineral after its characteristic lavender blue color.

Type material of the mineral is kept in the mineralogical collection of the TU Bergakademie Freiberg (catalog no. 20944 / b 8.1).

1877 was Goldsmith in La Blanco mine in Freirina ( Freirini ) in the Chilean de Atacama Región belonging Province Huasco some mineral samples were analyzed by William F. Foshag 1924th Due to the slight optical and chemical differences to the already known Lavendulan, Foshag decided that it was a new mineral and named it Freirinit based on its type locality . In 1957, however, C. Guillemin was able to use X-ray structure analysis to prove that Freirinit and Lavendulan showed the same reflex pattern. Freirinit was therefore identical to lavendulan and accordingly the mineral name was discredited and has been a synonym for lavendulan ever since .

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the lavendulan belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "water-containing phosphates with foreign anions ", where it was named after the "lavender group" with the system no. VII / D.25 and the other members Andyrobertsit , Attikait , Birchit , Calcio-Andyrobertsit , Englishit , Esperanzait , Goldquarryit , Lemanskiit , Mahnertit , Sampleit , Shubnikovit and Zdenĕkit .

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 lavendulan to the category of “phosphates etc. with 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 the additional anions to the phosphate, arsenate or vanadate complex (RO 4 ), so that the mineral can be classified according to its composition in the sub-section “With large and medium-sized cations; (OH etc.): RO 4  <0.5: 1 “can be found, where the“ lavender group ”with the system no. 8.DG.05 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns lavendulan to the class of "phosphates, arsenates and vanadates" and there to the category of "water-containing phosphates, etc., with hydroxyl or halogen". Here he is together with Lemanskiit, Mahnertit, Sampleit and Zdenĕkit in the unnamed group 42.09.04 within the subdivision “ Hydrous phosphates etc., with hydroxyl or halogen with (A) 3 (XO 4 ) 2 Z q  × x (H 2 O )" to find.

Crystal structure

Lavendulan crystallizes monoclinically in the space group P 2 1 / n (space group no. 14) with the lattice parameters a  = 10.011 (1)  Å ; b  = 19.478 (2) Å; c  = 10.056 (1) Å and β = 90.37 (1) ° and 4 formula units per unit cell .

properties

Lavender crystals are not very brittle, but very fragile and break easily. Lavendulan is very easy to melt in front of the soldering tube , during which the flame turns light blue due to the arsenic it contains. When heated in a glass flask, the mineral gives off crystal water .

Modifications and varieties

So far, only a simple, zinc-containing variety of Lavedulan is known, which was described by Clark in 1993 as an independent mineral and referred to as zinc lavendulan , but which lost its mineral status in November 2006 when the IMA was mass discredited .

Education and Locations

Macro shot of lavender crystals from Dolores prospecting , Pastrana , Murcia region , Spain (image width 1.5 mm)
Lavendulan (blue) and lammerite (greenish) from the El Guanaco Mine, Santa Catalina , Región de Antofagasta , Chile (size 5.0 cm × 3.6 cm × 2.6 cm)
Lavendulan as crack filling together with erythrin (purple) from the La Blanco Mine, Freirina , Región de Antofagasta , Chile (size: 7.7 cm × 5.8 cm × 5.4 cm)

Lavendulan forms secondarily in the oxidation zone of some copper deposits . As accompanying minerals may include Adamin , Antlerit , Brochantite , calcite , Chalkanthit , Chalkophyllit , Covellin , cuprite , Cyanotrichit , Erythrite , Fahleit , Geminit , gypsum , copper- Konichalcit , malachite , Mansfieldit , O'Danielit , Olivenit , Parnauit , quartz , Tennantit , Tsumcorite and cobalt-containing wad occur.

As a rather rare mineral formation, lavendulan can sometimes be abundant in various locations, but overall it is not very common. Around 150 sites are known to date (as of 2014). In addition to its type of locality , the “Alte Galilean Wirtschaft” mine near Frohnau and the Johanngeorgenstadt sites also in the Ore Mountains , the “Father Abraham” mine near Lauta (Marienberg) , the 137 shaft near Wolkenstein and the “Sauschwart” mine near Neustädtel (Schneeberg) in Saxony, the mineral was found in Germany in several places in the Black Forest such as in the Clara mine near Oberwolfach and in various mines near Wittichen in Baden-Württemberg; in a uranium mine near the Rudolfstein and a quarry near Dörrmorsbach in Bavaria; near Bad Lauterberg and Sankt Andreasberg in the Lower Saxony part of the Harz Mountains ; in various pits around Eiserfeld and Gosenbach as well as in the Thalburg mine near Heiligenhaus , the Eisenberg mine near Velbert and on the Maubacher Bleiberg in North Rhine-Westphalia; in the “Gertraud” ( Gertrud ) mine near Antweiler , the Friedrichssegen mine in the Lahn valley, the “Grüner Löwe” mine and the white mine near Imsbach in Rhineland-Palatinate and near Kamsdorf in Thuringia.

The only place of discovery in Austria so far is bird stop in the Schwarzleograben near Hütten (Leogang) in Salzburg.

In Switzerland, lavendulan has so far only been found in the Vaashöhle near Granges in the municipality of Sion ( Sion in French ) and in the “Kaltenberg” mine near Blüomatttälli in the Turtmann Valley in the canton of Valais.

The Gold Hill Mine near the place of the same name in Tooele County , Utah, where lavendulan crystals with a diameter of up to four millimeters emerged, is known for its exceptional lavender finds. Rich, needle-like aggregates are also known from the Talmessi mine near Anarak in the Iranian province of Isfahan .

Other locations include Argentina, Australia, Bolivia, Chile, France, Greece, Ireland, Italy, Canada, Morocco, Namibia, Portugal, Zimbabwe, South Africa, Spain, the Czech Republic, Hungary, the United Kingdom (England, Scotland) and in various states of the USA (Arizona, Michigan, Nevada).

See also

literature

  • JFA Breithaupt : Determination of new minerals. 3. Lavendulan. In: Journal for Practical Chemistry. Volume 10, 1837, pp. 505–506 ( PDF 751.8 kB )
  • C. Guillemin: Contribution a la minéralogie des arséniates, phosphates et vanadates de cuivre. I. Arséniates de cuivre. In: Bulletin de la Société Française de Minéralogie et de Cristallographie. Volume 79, 1956, pp. 7–95 ( PDF 487.6 kB ; Lavendulanite / Freirinite from p. 37)
  • Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke , Stuttgart 1978, ISBN 3-432-82986-8 , pp. 651 (first edition: 1891).
  • G. Giester, U. Kolitsch, P. Leverett, P. Turner, PA Williams: The crystal structures of lavendulan, sampleite, and a new polymorph of sampleite. In: European Journal of Mineralogy. Volume 19, 2007, pp. 75-93. doi: 10.1127 / 0935-1221 / 2007 / 0019-0075

Web links

Commons : Lavendulan  - Collection of images, videos and audio files

Individual evidence

  1. ↑ 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.  648 .
  2. ↑ Mineral Atlas: Lavendulan
  3. ^ A b 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.  507 .
  4. ↑ a b c G. Giester, U. Kolitsch, P. Leverett, P. Turner, PA Williams: The crystal structures of Lavendulan, sampleite, and a new polymorph of sampleite. In: European Journal of Mineralogy. Volume 19, 2007, pp. 75-93. doi: 10.1127 / 0935-1221 / 2007 / 0019-0075
  5. ↑ a b c d Lavendulan. In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America. 2001. ( PDF 65.6 kB )
  6. ↑ Webmineral - Lavendulan
  7. ↑ a b c d Mindat - Lavendulan
  8. ↑ Type material catalog of the University of Hamburg - Lavendulan
  9. ↑ William F. Foshag: Freirinite: A new mineral species. In: American Mineralogist. Volume 9, No. 2, February 1924, pp. 30-31. ( PDF 124 kB )
  10. ↑ C. Guillemin: New mineral names - Lavendulan (Freirinite = Lavendulan). In: American Mineralogist. Volume 42, Nos. 1 and 2, January-February 1957, pp. 123-124. ( PDF 463.9 kB )
  11. ↑ JFA Breithaupt : Determination of new minerals. 3. Lavendulan. In: Journal for Practical Chemistry. Volume 10, 1837, p. 505. ( PDF 751.8 kB )
  12. ↑ Ernst AJ Burke: A mass discreditation of GQN Minerals. In: The Canadian Mineralogist. Volume 44, 2006, pp. 1557-1560 doi: 10.2113 / gscanmin. 44.6.1557
  13. ↑ Mindat - Number of localities for Lavendulan
  14. ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia (=  Dörfler Natur ). Nebel Verlag, Eggolsheim 2002, ISBN 3-89555-076-0 .
  15. ↑ List of localities for Lavendulan in the Mineralienatlas and Mindat