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GEOREF RECORD

Crystal chemistry of two coexisting K-richterites from St. Marcel (Val d'Aosta, Italy)

Annibale Mottana and William L. Griffin
Crystal chemistry of two coexisting K-richterites from St. Marcel (Val d'Aosta, Italy)
American Mineralogist (December 1986) 71 (11-12): 1426-1433

Abstract

Two coexisting F-bearing K-richterites from the blueschist-facies metamorphic St Marcel Mn ore deposit have been studied by combined microprobe and IR analytical techniques. Despite their different colours (pink and blue) and cell dimensions, these amphiboles have formulae summing up to nearly 16 cations pfu on the basis of 22 O + 2(OH + F) and are chemically almost identical. The major differences are in the F/OH ratio and the Ca content, and significant minor differences occur in Fe and Ti. Site assignments based on probe and IR compare well with those determined by crystal-structure refinement. However, they also allow detection of empty A sites in the structure.


ISSN: 0003-004X
EISSN: 1945-3027
Coden: AMMIAY
Serial Title: American Mineralogist
Serial Volume: 71
Serial Issue: 11-12
Title: Crystal chemistry of two coexisting K-richterites from St. Marcel (Val d'Aosta, Italy)
Affiliation: Univ. Roma, Dip. Sci. Terra, Rome, Italy
Pages: 1426-1433
Published: 198612
Text Language: English
Publisher: Mineralogical Society of America, Washington, DC, United States
References: 41
Accession Number: 1987-045496
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables
N45°28'00" - N46°00'00", E06°47'60" - E07°58'00"
Secondary Affiliation: Mineral.-Geol. Mus., NOR, Norway
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 1987
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