Structural and chemical contrasts between prismatic and fibrous fluoro-edenite from Biancavilla, Sicily, Italy

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doi: 10.2113/gscanmin.45.2.249
Authors:Gianfagna, Antonio; Andreozzi, Giovanni B.; Ballirano, Paolo; Mazziotti-Tagliani, Simona; Bruni, Biagio M.
Author Affiliations:Primary:
Universita deglia Studi di Roma, Dipartimento di Scienze della Terra, Rome, Italy
Other:
Istituto Superiore di Sanita, Italy
Volume Title:Canadian Mineralogist
Source:The Canadian Mineralogist, Vol.45(Part 2), p.249-262. Publisher: Mineralogical Association of Canada, Ottawa, ON, Canada. ISSN: 0008-4476
Publication Date:2007
Note:In English. 32 refs.; illus., incl. 10 tables, sketch map
Summary:Fluoro-edenite, NaCa2Mg5(Si7Al)O22F2, occurs with both prismatic [A.M.86-1489] and fibrous morphologies in altered volcanic products at Monte Calvario, on the flanks of Mt Etna, Sicily. New crystal-chemical and structural data are reported for the fibrous variety. SEM-EDS microanalyses and Mössbauer spectroscopy indicate a variable composition for the fibres, ranging mostly from fluoro-edenite to winchite, tremolite and richterite compositions. From a combination of the microchemical, Mössbauer Fe3+/Fetot values and crystal structure refinement, the chemical formula is (Na0.307K0.157)(Ca1.505Na0.495)([6]Al0.104Fe3+0.333Fe2+0.162Mg4.255Ti0.062Mn0.063)(Si7.520[4]Al0.480)O22(F1.970Cl0.020). The cell parameters and site scattering were refined. Fe2+ was assigned to the M2 and M3 sites, and all Fe3+ was assigned to the M2 site. The Fe2+ content of each M2 site is far greater than that of M3. The interactions between mineral fibre and the biological environment are related strongly to the crystal chemistry of this fibrous amphibole. [R.A.H.]
Sections:Environmental studies; Mineral data
Mineral Groups:Double-chain silicates
Subjects:Amphibole group; Cell dimensions; Chain silicates; Clinoamphibole; Crystal chemistry; Crystal form; Crystal structure; Edenite; Formula; Lattice parameters; Mossbauer spectra; Richterite; Rietveld refinement; SEM data; Silicates; Spectra; X-ray diffraction data; Europe; Italy; Mount Etna; Sicily Italy; Southern Europe; Fluoro-edenite
Coordinates:N374500 N374500 E0150100 E0150100
Abstract Numbers:07M/2138
Record ID:2007098426
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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