Jungit

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Jungit
Jungite-82563.jpg
Light yellow jungite crystals from Hagendort -Süd / Waidhaus , Upper Palatinate, Bavaria (field of view 2 mm)
General and classification
other names

IMA 1977-034

chemical formula Ca 2 Fe 3+ 8 Zn 4 [OH | PO 4 ] 9 · 16H 2 O
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates
System no. to Strunz
and to Dana 		8.DJ.25 ( 8th edition : VII / D.37)
42.13.04.01
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol pyramidal mm 2 or dipyramidal 2 / m  2 / m  2 / m
Room group (no.) Pcm 2 1 , Pc 2 m or Pcmm (No. 26, 28 or 51)
Lattice parameters a  = 11.98  Å ; b  = 20.37 Å; c  = 9.95 Å
Formula units Z  = 2
Frequent crystal faces {010}, {201}, {100}
Physical Properties
Mohs hardness 1
Density (g / cm 3 ) measured: 2.843; calculated: 2.849
Cleavage completely ( mica-like ) according to {010}
Break ; Tenacity not defined
colour yellow to greenish yellow
Line color yellow
transparency translucent
shine Glass gloss, silk gloss
Crystal optics
Refractive indices n α  = 1.658
n β  = 1.658
n γ  = 1.664
Birefringence δ = 0.006
Optical character biaxial negative
Axis angle 2V = 60 ° (measured)

Jungite is a very rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the orthorhombic crystal system with the chemical composition Ca 2 Fe 3+ 8 Zn 4 [OH | PO 4 ] 9 · 16H 2 O, so chemically speaking it is a water-containing calcium - iron - zinc phosphate with additional hydroxide ions .

Jungite is translucent and usually develops yellow to greenish-yellow, tabular crystals up to about one centimeter in size, which are arranged in rosette-shaped aggregates . The crystal surfaces show a glass-like sheen , but polycrystalline aggregate forms shimmer more like silk.

With a Mohs hardness of 1, jungite, like the reference mineral talc, is one of the soft minerals whose surface can be scraped off with a fingernail.

Etymology and history

Jungite was first discovered in the pegmatites of the Cornelia pit near Hagendorf -Süd in the Upper Palatinate municipality of Waidhaus in Bavaria and described in 1980 by PB Moore and J. Ito, who named the mineral in honor of its discoverer Dr. Gerhard Jung (from Albbruck ) named.

classification

In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the jungit belonged to the department of "water-containing phosphates with foreign anions ", where together with parwanit it formed the unnamed group VII / D.37 .

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 the Jungit to the section and sub-section of the same name 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  = 1: 1 “can be found where it is the only member of the unnamed group 8.DJ.25 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns jungite to the class of "phosphates, arsenates and vanadates" and there to the category of "water-containing phosphates, etc., with hydroxyl or halogen". Here he can be found as the only member of the unnamed group 42.13.04 .

Education and Locations

Jungite forms in complex granite - pegmatites , where it can occur in association with mitridatite and various manganese oxides .

In addition to its type locality Grube Cornelia, the mineral could so far (as of 2013) only be detected in the nearby Waidhauser silver mine in Bavaria (Germany). Another possible location, the Foote Lithium Co. Mine near Kings Mountain (North Carolina) in the USA, has not yet been confirmed.

Crystal structure

Jungite crystallizes orthorhombically in the space group Pcm 2 1 , Pc 2 m or Pcmm (space group no. 26, 28 or 51) with the lattice parameters a  = 11.98  Å ; b  = 20.37 Å and c  = 9.95 Å as well as 2 formula units per unit cell .

See also

literature

  • PB Moore, Jun Ito: Jungit and Matulait, two new tabular phosphate minerals , In: Der Aufschluss (Journal of the VFMG ), Volume 31 (1980), pp. 55-61
  • Michael Fleischer, Louis J. Cabri, George Y. Chao, Adolf Pabst: New Mineral Names , In: American Mineralogist , Volume 65 (1980), pp. 1065-1070 ( PDF 703.6 kB ; Jungite and Matulaite, p. 3)
  • 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 .

Web links

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

Individual evidence

  1. ↑ 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.  513 .
  2. ↑ a b c d e Jungite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 415.9 kB )
  3. ↑ a b c d Mindat - Jungite
  4. ^ Mineral Atlas: Jungit