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Barquillite, Cu (sub 2) (Cd, Fe)GeS (sub 4) , a new mineral from the Barquilla Deposit, Salamanca, Spain

Ascension Murciego, M. Inmaculada Pascua, Jean Babkine, Yves Dusausoy, Olaf Medenbach and Hans-Juergen Bernhardt
Barquillite, Cu (sub 2) (Cd, Fe)GeS (sub 4) , a new mineral from the Barquilla Deposit, Salamanca, Spain
European Journal of Mineralogy (February 1999) 11 (1): 111-117


Barquillite, ideally Cu (sub 2) (Cd, Fe)GeS (sub 4) , is a new mineral species found in the Barquilla Sn-Ge-Cd-Cu-Fe vein-type deposit, Salamanca, Spain. This mineral occurs as plates and rosette-like aggregates of thin platy crystals, less than 50 mu m in size. It is commonly in contact with tetrahedrite and chalcopyrite, less so with bornite, mawsonite, stannite and stannoidite. Barquillite is opaque, with a metallic luster. In reflected light, it has a grey colour with a violet tint, very weak pleochroism, very weak bireflectance, and is very weakly anisotropic. Reflectance spectra are given. The micro-indentation hardness ranges between 180 and 300 kg/mm (super 2) . The mean of thirty four analyses gives: Cu 30.67, Ag 0.26, Cd 20.38, Fe 2.20, Mn 0.43, Zn 0.09, Ge 14.99, Sn 0.17, Sb 0.09, Bi 0.16, Ga 0.05, S 29.42, a total of 98.91 wt.%, corresponding to: (Cu (sub 2.10) Ag (sub 0.01) ) (sub Sigma 2.11) (Cd (sub 0.79) Fe (sub 0.17) Mn (sub 0.03) Zn (sub 0.01) ) (sub Sigma 1.00) ( Ge (sub 0.90) Sn (sub 0.01) ) (sub Sigma 0.91) S (sub 3.98) (on the basis of 8 atoms) or simply Cu (sub 2) (Cd, Fe)GeS (sub 4) . Based on the empirical formula and Z = 2, Dcalc = 4.53 g/cm (super 3) . The X-ray powder diffraction pattern obtained is analogous to that of briartite (JCPDS 25-282). The strongest X-ray powder diffraction lines are (d in A(I)(hkl)): 3.10(100)( 112), 1.92(80)(220), 1.89(70)(204), 1.64(60)(312), 1.60(20)(303, 116) and 2.73(10)(200). The refinement of the lattice parameters leads to a = 5.45(4) A and c = 10.6(1) A, indexed by analogy to briartite. Barquillite is therefore a member of the stannite group, the Cd-dominant analogue of briartite. The name is given after the village of Barquilla, very near the type locality.

ISSN: 0935-1221
Serial Title: European Journal of Mineralogy
Serial Volume: 11
Serial Issue: 1
Title: Barquillite, Cu (sub 2) (Cd, Fe)GeS (sub 4) , a new mineral from the Barquilla Deposit, Salamanca, Spain
Affiliation: Universidad de Extremadura, Facultad de Ciencias, Badajoz, Spain
Pages: 111-117
Published: 199902
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 27
Accession Number: 1999-033847
Categories: Mineralogy of non-silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables
N40°13'00" - N41°17'60", W06°52'00" - W05°07'60"
Secondary Affiliation: Universidad de Salamanca, ESP, SpainUniversite Henri Poincare, FRA, France
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 199912
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