The behaviour of Mn in amphiboles; Mn in synthetic fluor-edenite and synthetic fluor-pargasite

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doi: 10.1127/ejm/9/1/0115
Authors:Oberti, Roberta; Hawthorne, Frank C.; Raudsepp, Mati
Author Affiliations:Primary:
CNR-Centro di Studio per la Cristallochimica e la Cristallografia (CSC), Pavia, Italy
Other:
University of British Columbia, Canada
Volume Title:European Journal of Mineralogy
Source:European Journal of Mineralogy, 9(1), p.115-122. Publisher: Schweizerbart'sche Verlagsbuchhandlung (Nägele u. Obermiller), Stuttgart, Federal Republic of Germany. ISSN: 0935-1221
Publication Date:1997
Note:In English. 18 refs.; 7 tables
Summary:The crystal structures of two synthetic C2/m amphiboles, manganoan fluor-edenite Na1.06(Ca1.41Na0.12Mn0.47)(Mg4.44Mn0.41Al0.15)(Si6.91Al1.09)O22F2, with a 9.829, b 18.024, c 5.284 Å, β 104.66°, and manganoan fluor-pargasite (Na0.96Ca0.13)(Ca1.51Mn0.40)(Mg3.47Mn0.73Al0.80)(Si5.95Al2.05)O22F2, with a 9.812, b 17.926, c 5.308 Å, β 105.10° have been refined to R 2.0 and 1.4%, respectively. Site-scattering and EPMA data both indicate that there is a large amount (∼ 0.50 pfu) of Mn2+ at the M4 site in both these synthetic amphiboles. C-group Mn2+ shows the ordering pattern M2 >><[dollar]I>>><[dollar]I> M1 >><[dollar]I>>><[dollar]I> M3 in these amphiboles; this is a significantly different behaviour from that of Fe2+ which shows the ordering pattern M1 up to M3 in Mn-poor calcic, sodic-calcic and alkali amphiboles. The presence of significant Ca at the A site in F-rich pargasite is also confirmed. [R.A.H.]
Subjects:Amphibole group; Chain silicates; Clinoamphibole; Crystal structure; Edenite; Manganese; Metals; Pargasite; Refinement; Silicates; Synthesis; Fluor-edenite; Fluor-pargasite
Abstract Numbers:97M/2456
Record ID:1997030096
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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