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GEOREF RECORD

Graulichite-(Ce), a new arsenate mineral from the Stavelot Massif, Belgium

Frederic Hatert, Pierre Lefevre, Marco Pasero and Andre-Mathieu Fransolet
Graulichite-(Ce), a new arsenate mineral from the Stavelot Massif, Belgium
European Journal of Mineralogy (August 2003) 15 (4): 733-739

Abstract

Graulichite-(Ce), ideally CeFe (super 3+) (sub 3) (AsO (sub 4) ) (sub 2) (OH) (sub 6) , is a new mineral species from Hourt, Stavelot Massif, Belgium. It occurs in the most altered parts of a Devillian quartzite (Lower to Middle Cambrian), in close association with arsenopyrite, scorodite, mimetite, pharmacosiderite, and goethite. Graulichite-(Ce) forms 80 to 150 mu m spherical aggregates of rhombohedral crystals, 50 to 80 mu m length, which show the forms {1012} and {1011}. The mineral is transparent and exhibits a light-green to brownish colour, with a resinous lustre. It is non-fluorescent and shows an irregular fracture, without any perceptible cleavage. The calculated density is 4.42 g/cm (super 3) . Graulichite-(Ce) is uniaxial negative, with a mean refractive index close to 1.97(1) (lambda = 590 nm), pleochroic from light green to yellowish. Electron microprobe analyses gave As (sub 2) O (sub 5) 31.20, P (sub 2) O (sub 5) 0.03, SO (sub 3) 0.06, SiO (sub 2) 0.03, Al (sub 2) O (sub 3) 3.09, Fe (sub 2) O (sub 3) 30.65, SrO 0.24, PbO 0.07, BaO 3.95, CaO 0.03, La (sub 2) O (sub 3) 2.26, Ce (sub 2) O (sub 3) 15.73, Nd (sub 2) O (sub 3) 2.08, H (sub 2) O (calc.) 8.37, total 97.79 wt.%. The resulting empirical formula, calculated on the basis of 6 cations, is (Ce (sub 0.67) Ba (sub 0.18) La (sub 0.10) Nd (sub 0.09) Sr (sub 0.02) ) (sub Sigma 1.06) (Fe (super 3+) (sub 2.68) Al (sub 0.42) ) (sub Sigma 3.10) [(As (sub 1.89) S (sub 0.01) [] (sub 0.10) ) (sub Sigma 2.00) O (sub 8) ] [(OH) (sub 5.57) (H (sub 2) O) (sub 0.43) ] (sub Sigma 6.00) . The single-crystal unit-cell parameters are a = 7.288(2) and c = 16.812(9) Aa, space group R3m. The seven strongest lines in the X-ray powder-diffraction pattern [d(in Aa)(I)(hkil)] are: 3.052(100)(1123), 3.636(40)(1120), 2.239(35)(1017), 1.817(35)(2240), 2.792(30)(0006), 5.906(25)(1011), 1.968(25)(3033). Graulichite-(Ce) is the iron analogue of arsenoflorencite-(Ce), and belongs to the crandallite mineral group, with the alunite-type structure. The crystal structure of graulichite-(Ce) has been refined, based on single-crystal X-ray diffraction data, to R = 0.048.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 15
Serial Issue: 4
Title: Graulichite-(Ce), a new arsenate mineral from the Stavelot Massif, Belgium
Affiliation: Universite de Liege, Laboratoire de Mineralogie, Liege, Belgium
Pages: 733-739
Published: 200308
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 39
Accession Number: 2003-070566
Categories: Mineralogy of non-silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 7 tables
N49°30'00" - N50°30'00", E04°10'00" - E05°30'00"
N49°30'00" - N51°30'00", E02°30'00" - E06°30'00"
N50°25'00" - N50°25'00", E05°55'60" - E05°55'60"
Secondary Affiliation: Universita di Pisa, ITA, Italy
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 200321
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