Barquillit

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Barquillit
General and classification
other names

IMA 1996-050

chemical formula Cu 2 (Cd, Fe) GeS 4
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.KA.10 ( 8th edition : II / C.06)
02.09.02.11
Crystallographic Data
Crystal system tetragonal
Crystal class ; symbol tetragonal-scalenohedral; 4 2 m
Room group (no.) I 4 2 m (No. 121)
Lattice parameters a  = 5.45  Å ; c  = 10.61 Å
Formula units Z  = 2
Physical Properties
Mohs hardness 4 to 4.5
Density (g / cm 3 ) calculated: 4.53
Cleavage Please complete!
colour gray with a tinge of purple
Line color Please complete!
transparency opaque
shine Metallic luster

Barquillite is a very rarely occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the tetragonal crystal system with the chemical composition Cu 2 (Cd, Fe) GeS 4 and is thus the cadmium analogue of Briartite (Cu 2 (Zn, Fe) GeS 4 ). The elements cadmium and iron indicated in the round brackets can represent each other in the formula ( substitution , diadochie), but are always in the same proportion to the other components of the mineral.

Barquillite is opaque in every form and only develops small, tabular crystals up to about 50 μm in rosette-shaped mineral aggregates of gray, metallic shimmering color with a tinge of purple.

Etymology and history

Barquillit was first discovered in 1996 in the "Fuentes Villanas Mine" near Barquilla in the province of Salamanca in the autonomous Spanish region of Castile-León. It was described in 1999 by A. Murciego, I. Pascua, J. Babkine, Y. Dusausoy, O. Medenbach and H.-J. Bernhardt, who named the mineral after the city closest to the type locality .

classification

In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the barquillite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides with the molar ratio of metal: sulfur, selenium, tellurium ≈ 1: 1", where together with Briartit , Černýit , Famatinit , Ferrokësterit , Hocartit , Kësterit , Kuramit , Luzonit , Permingeatit , Petrukit , Pirquitasit , Rhodostannit , Sakuraiit , Stannit , Toyohait and Velikit the "Stannit-Gruppe" with the system no. II / C.06 formed.

The 9th edition of Strunz's mineral systematics, which has been in force since 2001 and is used by the International Mineralogical Association (IMA), also assigns barquillite to the class of "sulfides and sulfosalts", but in the "sulfarsenates" category. This department is further subdivided according to the crystal structure, so that the mineral can be found in the subdivision of "Sulpharsenates with (As, Sb) S 4 tetrahedra" according to its structure , where it can be found together with Briartite, Famatinite, Luzonite and Permingeatite "Luzonit Group" with the system no. 2.KA.10 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the barquillite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here it is together with Hocartit, Briartit, Černýit, Ferrokësterit, Kësterit, Kuramit, Pirquitasit, Sakuraiit, Stannit and Velikit in the "stannite group (tetragonal: I 4 2 m ) A 2 BCS type" with the system no. 02.09.02 within the subsection " Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 1: 1 ".

Education and Locations

Barquillit formed hydrothermally in tin -, germanium -, cadmium, copper - and iron-containing transition - deposits . The accompanying minerals include bornite , chalcopyrite , diginite , greenockite , mawsonite , mohite , stannite , stannoidite and tetrahedrite .

So far (as of 2012) Barquillit could only be found at its type locality "Fuentes Villanas Mine" in Spain.

Crystal structure

Barquillite crystallizes tetragonally in the space group I 4 2 m (space group no. 121) with the lattice parameters a  = 5.45  Å and c  = 10.61 Å as well as 2 formula units per unit cell .

See also

Web links

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.  79 .
  2. ↑ Webmineral - Barquillite
  3. ↑ John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols: Barquillite , in: Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 60.2 kB )
  4. ↑ A. Murciego, I. Pascua, J. Babkine, Y. Dusausoy, O. Medenbach and H.-J. Bernhardt: Barquillite, Cu 2 (Cd, Fe) GeS 4 , a new mineral from the Barquilla deposit, Salamanca, Spain , in John L. Jambor, Andrew C. Roberts: New Mineral Names , American Mineralogist, Volume 84 (1999), P. 1464–1468 ( PDF 261.6 kB )
  5. ^ Mindat - Barquillite