Yazganit

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Yazganit
General and classification
other names

IMA 2003-033

chemical formula
  • Na (Mg, Mn) Fe 3+ 2 [AsO 4 ] 3 · H 2 O
  • NaMgFe 3+ 2 (AsO 4 ) 3 · H 2 O
Mineral class
(and possibly department) 		Phosphates, arsenates, vanadates
System no. to Strunz
and to Dana 		8.AC.10 ( 8th edition : VII / A.07)
02.38.03.10
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group C 2 / c (No. 15)Template: room group / 15
Lattice parameters a  = 12.181 (1)  Å ; b  = 12.807 (1) Å; c  = 6.6391 (5) Å
β  = 112.441 (9) °
Formula units Z  = 4
Physical Properties
Mohs hardness 5
Density (g / cm 3 ) measured: 4.18 (2); calculated: 4.182 (1)
Cleavage no
Break ; Tenacity clamshell; brittle
colour brown to almost black
Line color light brown, yellowish gray
transparency translucent
shine Metallic luster, diamond luster
Crystal optics
Refractive indices n α  = 1.870
n β  = 1.897
n γ  = 1.900
Birefringence δ = 0.030
Optical character biaxial negative
Axis angle 2V = 35 °

Yazganite is a rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates " with the idealized chemical composition NaMgFe 3+ 2 (AsO 4 ) 3 · H 2 O and is therefore chemically a water-containing sodium - magnesium - iron - arsenate . Since part of the magnesium is often replaced ( substituted ) by manganese in natural yazganite samples , the formula is also given in various sources as Na (Mg, Mn) Fe 2 3+ [AsO 4 ] 3 · H 2 O.

Yazganite crystallizes in the monoclinic crystal system and develops either individual prismatic crystals or mineral aggregates from well-formed crystals up to about 10 mm in size with a metallic to diamond-like shine on the surfaces. The mineral is translucent and brown to almost brown-black in color. Its line color , on the other hand, is rather light brown to yellowish gray.

Etymology and history

Yazganite was first discovered by the Turkish geologist Evren Yazgan (* 1943), who collected mineral samples at the Erciyes Dağı volcanic complex in the Turkish province of Kayseri . The analysis and initial description was carried out by Halil Sarp and Radovan Černý , who named the mineral after its discoverer and submitted their test results and the chosen name to the International Mineralogical Association (IMA) for examination in 2003 (internal IMA No. 2003-033). The first description was published two years later in the European Journal of Mineralogy .

The type material of the mineral is stored in the mineralogical department of the Muséum d'histoire naturelle de la Ville de Genève in Geneva , Switzerland under catalog no. 478,188 kept.

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the yazganite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department "anhydrous phosphates [PO 4 ] 3− , without foreign anions ", where he together with Bradaczeckit , Johillerit , Nickenichit and O'Danielit (Odanielit) formed the unnamed group VII / A.07 .

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 Yazganite to the category of “phosphates etc. without additional anions; without H 2 O “. This is, however, further subdivided according to the relative size of the cations involved , so that the mineral can be found according to its composition in the sub-section "With medium-sized and large cations", where it is found together with alluaudite , arseniopleit , bradaczekite, groatite , karyinite , ferroalluaudite , Ferrohagendorfit , Hagendorfit , Johillerit, Maghagendorfit , Manitobait , Nickenichit, O'Danielit and Varulith the "Hagendorfitgruppe" with the system no. 8.AC.10 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Yazganite to the class of "Phosphates, Arsenate and Vanadates" and there in the department of "@@@" Here he is the only member / together with the " Alluaudit-Wyllieitgruppe (Alluaudit-Untergruppe) " with the system no. 38.02.03 within the sub-section "Anhydrous phosphates etc., (A + B 2+ ) 5 (XO 4 ) 3 ".

Crystal structure

Yazganite crystallizes monoclinically in the space group C 2 / c (space group no. 15) with the lattice parameters a  = 12.181 (1)  Å ; b  = 12.807 (1) Å, c  = 6.6391 (5) Å and β = 112.441 (9) ° as well as four formula units per unit cell . Template: room group / 15

Education and Locations

Yazganit formed hydrothermally in the existing at the site, volcanic andesite - rock . Accompanying minerals are auripigment , cassiterite , hematite , magnetite , realgar and tridymite .

Yazganit has so far only been found at its type locality Erciyes Dağı in Turkey.

See also

literature

Web links

Individual evidence

  1. ↑ a b 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 .
  2. ↑ a b IMA / CNMNC List of Mineral Names; March 2018 (English)
  3. ↑ Webmineral - Yazganite (English)
  4. ↑ a b c d Halil Sarp, Radovan Černý: Yazganite, NaFe 3+ 2 (Mg, Mn) (AsO 4 ) 3H 2 O, a new mineral: its description and crystal structure . In: European Journal of Mineralogy . tape 17 , no. 2 , 2005, p. 367–373 , doi : 10.1127 / 0935-1221 / 2005 / 0017-0367 ( brief description from pubs.geoscienceworld.org [accessed July 2, 2018]).
  5. ↑ a b c d e f g Yazganite . 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; 131  kB ; accessed on July 2, 2018]).
  6. ↑ a b c d e f Mindat - Yazganite (English)
  7. ↑ Find location list for Yazganit at the Mineralienatlas and at Mindat