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Fluoro-magnesiohastingsite from Dealul Uroi (Hunedoara County, Romania); mineral data and crystal structure of a new amphibole end-member

Hans-Peter Bojar and Franz Walter
Fluoro-magnesiohastingsite from Dealul Uroi (Hunedoara County, Romania); mineral data and crystal structure of a new amphibole end-member
European Journal of Mineralogy (August 2006) 18 (4): 503-508

Abstract

Fluoro-magnesiohastingsite occurs in small cavities of an altered hematite-rich xenolith in the Quaternary trachyandesite at Dealul Uroi, Hunedoara county, Romania, associated with titaniferous hematite, augite, phlogopite, enstatite, feldspar, tridymite, titanite, fluorapatite, ilmenite and pseudobrookite. It is reddish brown to yellowish and has a perfect {110} cleavage; H. 6, D (sub calc) 3.18 g/cm (super 3) ; alpha (yellowish brown) 1.642, beta (light brown) 1.647, gamma (light brown) 1.662, 2V (sub gamma ) 61 degrees ; beta = b, O.A.P. (010), gamma : c 26 degrees . EPMA results correspond with the empirical formula (super A) (Na (sub 0.50) K (sub 0.27) Ca (sub 0.17) (super B) Ca (sub 2.00) (super C) (Mg (sub 4.03) Fe (super 3+) (sub 0.70) Al (sub 0.13) Ti (sub 0.13) ) (super T) (Si (sub 5.89) Al (sub 2.11) )O (sub 22) F (sub 2) . Indexed XRD powder data are tabulated; strongest lines 3.124(100), 8.421(61), 2.700(54), 3.377(44), 2.932(35) Aa; a 9.871, b 18.006, c 5.314 Aa, beta 105.37 degrees , V 910.7 Aa (super 3) , Z = 2, space group C2/m. The crystal structure was refined to R 0.054; there is an ordering of Fe (super 3+) at M2. The A site-scattering values show significant Ca (0.19 pfu) as well as K and Na at the Am and A2 sites. The site-scattering value and bond-length of O3 to cations indicate that this site is occupied by F; this was confirmed by IR spectroscopy. Most of the associated minerals also contain fluorine, as do the amphiboles in the host trachyandesite; EPMA values are reported.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 18
Serial Issue: 4
Title: Fluoro-magnesiohastingsite from Dealul Uroi (Hunedoara County, Romania); mineral data and crystal structure of a new amphibole end-member
Affiliation: Landesmuseum Joanneum, Department of Mineralogy, Graz, Austria
Pages: 503-508
Published: 200608
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 18
Accession Number: 2006-069707
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 7 tables, anals.
N45°14'40" - N46°19'60", E22°21'00" - E23°37'00"
Secondary Affiliation: Karl-Franzens-University Graz, AUT, Austria
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 200640
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