Veszelyite

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Veszelyite
Veszelyite-37782.jpg
Veszelyite crystal from the Black Pine Mine, Flint Creek Valley, John Long Mts, Philipsburg , Granite County , Montana, USA (size: 2.2 cm × 1.4 cm × 1.1 cm)
General and classification
chemical formula (Cu, Zn) 2 [6] Zn [4] [(OH) 3 | PO 4 ] • 2H 2 O
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates
System no. to Strunz
and to Dana 		8.DA.30 ( 8th edition : VII / D.19)
02.02.03.01
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  = 9.83  Å ; b  = 10.22 Å; c  = 7.53 Å
β  = 103.2 °
Formula units Z  = 4
Frequent crystal faces {100}, {011}, {001}, {110}, {111}, {121}
Physical Properties
Mohs hardness 3.5 to 4
Density (g / cm 3 ) measured: 3.4 (1); calculated: 3.42
Cleavage good after {001} and {110}
colour greenish blue to dark blue
Line color blue
transparency translucent
shine Glass gloss
Crystal optics
Refractive indices n α  = 1.618 to 1.640
n β  = 1.622 to 1.658
n γ  = 1.658 to 1.695
Birefringence δ = 0.040 to 0.055
Optical character biaxial positive
Axis angle 2V = 35 to 71 ° (measured); 38 to 72 ° (calculated)
Pleochroism weak: Z = blue; X = greenish blue

Veszelyite is a rarely occurring mineral from the mineral class of "phosphates, arsenates and vanadates". It crystallizes in the monoclinic crystal system with the chemical composition (Cu, Zn) 2 [6] Zn [4] [(OH) 3 | PO 4 ] · 2H 2 O and is thus chemically a water-containing copper - zinc - phosphate with additional hydroxide ions . Since the copper in the compound can be partially replaced ( substituted ) by zinc , this is indicated by round brackets around the two elements.

Veszelyite develops thick-tabular to short-prismatic, pseudo- octahedral crystals , but also occurs in the form of granular mineral aggregates and bark-like crusts. The translucent crystals are greenish blue to dark blue in color and have a glass-like sheen on the surface .

With a Mohs hardness of 3.5 to 4, Veszelyite is one of the medium-hard minerals that, like the reference minerals calcite (Mohs hardness 3) and fluorite (Mohs hardness 4), can be easily scratched with a pocket knife .

Etymology and history

Blue-green veszelyite from the type locality Ocna de Fier, Romania ( overall size 11.2 cm × 8.3 cm × 4.0 cm)

Veszelyite was first discovered in the area of Ocna de Fier near Morawitz ( Morawicza ) in the historical region of Banat in what is now Romania and described in 1874 by Albrecht Schrauf (1837-1897), who named the mineral after its discoverer, the Hungarian mining engineer A. Veszeli (1820-1888) named.

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , veszelyite 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 "veszelyite" Group "with the system no. VII / D.19 and the other members Kipushit and Philipsburgit .

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 veszelyite to the category of “phosphates etc. with additional anions; with H 2 O “. This, however, is further divided according to the relative size of the participating cations , so that the mineral can be found according to its composition in the subsection "With small (and sometimes large) cations" where there is the only member of the unnamed group 8.DA.30 forms .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns veszelyite 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 to be found as the only member of the unnamed group 42.02.03 within the subdivision “ Water-containing phosphates etc., with hydroxyl or halogen with (AB) 3 (XO 4 ) Z q × x (H 2 O) ”.

Crystal structure

Veszelyite crystallizes monoclinically in the space group P 2 1 / a (space group no. 14, position 3) with the lattice parameters a  = 9.83  Å ; b  = 10.22 Å; c  = 7.53 Å and β = 103.2 ° and 4 formula units per unit cell . Template: room group / 14.3

Education and Locations

Dark blue veszelyite crust coated with light blue hemimorphite from the Laochang ore field, Gejiu , Honghe Autonomous District, Yunnan, China ( overall size 5.5 cm × 3.6 cm × 1.8 cm)

Veszelyite is a rare secondary mineral that forms in the oxidation zone of copper-zinc deposits . As accompanying minerals may include Aurichalcit , Brochantite , Hemimorphite , Kipushit , Libethenit , malachite , Pseudomalachit , Pyromorphite , quartz and Vauquelinite occur.

As a rare mineral formation, Veszelyite could only be detected at a few sites, with around 20 sites being known to date (as of 2014). Its type locality Ocna de Fier is the only known site in Romania so far.

The Black Pine mine near Philipsburg in the US state of Montana, where crystals of up to five centimeters in length emerged, is known for its extraordinary veszelyite finds .

Other previously known sites include the Mi-Fiel-Rosita mine near Vallenar in the Chilean Región de Atacama, the Laochang ore field near Gejiu in the Chinese province of Yunnan, the Kipushi mine in the Democratic Republic of the Congo, the ancient slag heaps near Lavrio in the Greek region of Attica , Villaputzu on the island of Sardinia, which belongs to Italy, several places on the Japanese island of Honshū , the Esperanza mine near Zacapoaxtla in the Mexican state of Puebla , the Kabwe mine (Broken Hill Mine) in Zambia, the Sanyati mine in Zimbabwe, Wanlockhead in Scotland (United Kingdom) and Ahmeek ( Keweenaw County ) in Michigan, Black Pine Ridge ( Granite County ) in Montana and the Bristol Silver Mine near Bristol and Jackrabbit ( Lincoln County ) in Nevada in the United States of America.

See also

literature

  • A. Schrauf: Investigation of a new mineral called Veszelyit . In: Gazette of the Imperial Academy of Sciences . tape 11 , 1874, p. 135–137 ( rruff.info [PDF; 245 kB ; accessed on January 9, 2018]).
  • S. Ghose, SR Leo, C. Wan: Structural chemistry of copper and zinc minerals. Part I. Veszelyite, (Cu, Zn) 2 ZnPO 4 (OH) 3 · 2H 2 O: a novel type of sheet structure and crystal chemistry of copper-zinc substitution . In: American Mineralogist . tape 59 , 1974, pp. 573-581 ( rruff.info [PDF; 1.1 MB ; accessed on January 9, 2018]).
  • Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke , Stuttgart 1978, ISBN 3-432-82986-8 , pp. 650 (first edition: 1891).
  • 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. 647 .

Web links

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

Individual evidence

  1. ↑ a b c d e 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.  494 .
  2. ↑ Webmineral - Veszelyite
  3. ↑ a b c Veszelyite . 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; 65  kB ; accessed on January 9, 2018]).
  4. ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
  5. ↑ a b c d e f Mindat - Veszelyite
  6. ↑ Mindat - Number of localities for Veszelyite
  7. ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia (=  Dörfler Natur ). Nebel Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 185 .
  8. ↑ Find location list for Veszelyit in the Mineralienatlas and in Mindat