Wagnerite

from Wikipedia, the free encyclopedia
Wagnerite
General and classification
other names

Kjerulfin

chemical formula Mg 2 [F | PO 4 ]
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates
System no. to Strunz
and to Dana 		8.BB.15 ( 8th edition : VII / B.03)
41.06.02.01
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group P 2 1 / a (No. 14, position 3)Template: room group / 14.3
Lattice parameters a  = 12.07  Å ; b  = 12.53 Å; c  = 9.66 Å
β  = 108.5 °
Formula units Z  = 16
Physical Properties
Mohs hardness 5 to 5.5
Density (g / cm 3 ) measured and calculated: 3.15
Cleavage imperfect after {100} and {120}
Break ; Tenacity uneven, slightly mussel-like, splintery
colour Wine to honey yellow, orange, yellowish brown, light gray, white, also meat red or light green
Line color White
transparency transparent to opaque
shine Glass gloss to weak resin gloss
Crystal optics
Refractive indices n α  = 1.568
n β  = 1.572
n γ  = 1.582
Birefringence δ = 0.015
Optical character biaxial positive
Axis angle 2V = measured: 25 to 35 °

Wagnerite (also synonymous with kjerulfine ) is a rarely occurring mineral from the mineral class of "phosphates, arsenates and vanadates". It crystallizes in the monoclinic crystal system with the idealized chemical composition Mg 2 [F | PO 4 ] and is therefore a magnesium - phosphate with additional fluorine ions .

Since in naturally occurring Wagnerites small proportions of magnesium can be represented ( substituted ) by doubly positively charged iron ions or fluorine by hydroxide ions , the formula is sometimes used in various sources with (Mg, Fe 2+ ) 2 (PO 4 ) F or Mg 2 (PO 4 ) (F, OH).

The mineral usually develops short to long prismatic, longitudinally striped crystals , but also occurs in the form of granular or coarse or massive mineral aggregates .

In their pure form, Wagnerite crystals are colorless and transparent with a glass-like sheen on the surfaces. However, due to multiple refraction due to lattice construction defects or polycrystalline training, it can also appear white to light gray and, due to foreign admixtures, take on a wine to honey yellow, orange to flesh red, yellowish brown or light green color, with the transparency decreasing accordingly.

Etymology and history

Wagnerite was first described in 1821 by Johann Nepomuk Fuchs , who named the mineral in honor of the German Montanist Franz Michael von Wagner . He had discovered the mineral a few years earlier in Höllgraben near Imlau in the market town of Werfen in the Austrian state of Salzburg and gave Fuchs some fragments for analysis.

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , Wagnerite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "anhydrous phosphates, with foreign anions F, Cl, O, OH", where together with Hydroxylwagnerit , Joosteit , Magniotriplit (discredited 2004), Sarkinit , Staněkit , Triplit , Triploidit , Wolfeit and Zwieselit the "Zwieselit-Wolfeit-Gruppe" with the system no. VII / B.03 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), also assigns Wagnerite to the category of “phosphates etc. with additional anions; without 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 (OH etc.) to the phosphate, arsenate or vanadate complex (RO 4 ), so that the mineral according to its composition in the subsection “With exclusively medium-sized cations; (OH etc.): RO 4  ≤ 1: 1 “can be found, where together with Joosteit, Sarkinit, Staněkit, Triploidit and Wolfeit the“ Triploiditgruppe ”with the system no. 8.BB.15 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Wagnerite to the class of "phosphates, arsenates and vanadates" and there in the category of "anhydrous phosphates etc., with hydroxyl or halogen". Here he is only together with hydroxylwagnerite in the " Wagnerite group " named after him with the system no. 41.06.02 within the sub-section "Anhydrous phosphates etc., with hydroxyl or halogen with (A) 2 (XO 4 ) Z q ".

Crystal structure

Wagnerite crystallizes monoclinically in the space group P 2 1 / a (space group no. 14, position 3) with the lattice parameters a  = 12.07  Å ; b  = 12.53 Å; c  = 9.66 Å and β = 108.5 ° as well as 16 formula units per unit cell . Template: room group / 14.3

Education and Locations

Wagnerite forms as a rare accessory mineral in metamorphic rocks such as gneiss and eclogite , but can also magmatic in granitic pegmatites and hydrothermal in quartz - gears and salt deposits occur. As accompanying minerals may vary by locality, among other Lazulith , ferrous magnesite and various chlorites (Höllgraben, Australia); Andalusite , various apatites , biotite , corundum , monazite (Ce) , plagioclase , sillimanite and various tourmalines (Santa Fe Mountain, Colorado, USA) or chrysoberyl , cordierite , various garnets , magnesiota affide (formerly musgravite ), sapphirine and surinamite (Casey Bay , Antarctica).

As a rare mineral formation, Wagnerite could only be detected at a few sites, with around 50 sites being known to date (as of 2014). In addition to its type locality Höllgraben near Imlau and in Rettenbachgraben and Wengergraben, which are also located in the municipality of Werfen, the mineral was found in Austria in the Haagen quarry near Webing (municipality of Abtenau ), at Graulahnerkopf (Graulahnerkogel) in Amerbachtal (part of Felbertal ) two locations in the Fritztal ( Fritzbachtal ) and at the Klemmgraben on the Eiskogel in Salzburg as well as in rock samples that were taken during the construction of the Bosruck tunnel for the Pyhrn motorway in Upper Austria. Its type locality Höllgraben is also known as an outstanding find spot for particularly large Wagnerite crystals, mostly associated with lazulite, with a diameter of up to three centimeters.

In Germany, Wagnerite has so far performed on the Silberberg near Bodenmais in Lower Bavaria; on the Nickenicher Sattel near Eich (Andernach) , on the Emmelberg near Üdersdorf , in the Caspar quarry on the Ettringer Bellerberg near Ettringen and on the Wannenköpf near Ochtendung in the Rhineland-Palatinate Eifel and at Schneeberg in the Saxon Ore Mountains .

Other sites include in Enderbyland and Princess Elisabeth Land in East Antarctica , in South Australia and the offshore island of Tasmania , the Canadian provinces of Manitoba and Québec , in the Chinese autonomous region of Inner Mongolia , in the French department of Pyrénées-Orientales , on Vesuvius and in some places in the Italian region of Piedmont , in the Turkestan region in Kyrgyzstan, in several places in the Norwegian province of Telemark , in the Castelo Branco district in Portugal, in the Russian Oblast of Chelyabinsk , the Spanish municipalities of Salamanca and Alt Empordà , the Swedish regions of Södermanland and Värmland , in Bohemia and Carrots in the Czech Republic and in various places in the US states of Arizona , Colorado , California , Maine and New York .

See also

literature

  • Joh. Nep. Fuchs : About the Wagnerite. In: Journal for Chemistry and Physics. Volume 33, 1821, pp. 269-277. ( PDF 343 kB )
  • A. Coda, G. Giuseppetti, C. Tadini, SG Carobbi: The crystal structure of wagnerite. In: Atti della Accademia Nazionale dei Lincei. Volume 43, 1967, pp. 212-224.
  • K. Auh, FA Hummel: Solid solution in the wagnerite structure. In: The Canadian Mineralogist. Volume 12, 1974, pp. 346-351. ( PDF 509.4 kB )

Web links

Individual evidence

  1. ↑ a b Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke , Stuttgart 1978, ISBN 3-432-82986-8 , pp.  628 (first edition: 1891).
  2. ↑ a b c d e 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.  442 .
  3. ↑ Webmineral - Wagnerite
  4. ↑ a b c d Wagnerite. In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America. 2001. ( PDF 66.02 kB )
  5. ↑ a b c d e Mindat - Wagnerite
  6. ↑ a b c Petr Korbel, Milan Novák: Mineral Encyclopedia (=  Dörfler Natur ). Nebel Verlag, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 159 .
  7. ↑ Mindat - picture example with colorless, glass-shining Wagnerite crystals
  8. ↑ Mindat - picture example with polycrystalline, white Wagnerite crystals
  9. ↑ Joh. Nep. Fuchs : About the Wagnerite. In: Journal for Chemistry and Physics. Volume 33, 1821, pp. 269-277. ( PDF 343 kB )
  10. ↑ Mindat - Number of localities for Wagnerite
  11. ↑ Find location list for Wagnerite in the Mineralienatlas and Mindat