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Order-disorder in natrolite-group minerals

Alberto Alberti, Giuseppe Cruciani and Ilaria Dauru
Order-disorder in natrolite-group minerals
European Journal of Mineralogy (June 1995) 7 (3): 501-508


The refinement of the crystal structure of a natrolite from Palagonia, Sicily, closely intergrown in gonnardite, was carried out to study order-disorder in tetrahedral sites of natrolite-group minerals. About 20 % of Al has been found in Si1 and Si2 sites and 30 % of Si in the Al site. These results, together with chemical data, suggest that complete disorder cannot be reached in hydrothermal natrolites. The complete disorder found in gonnardites, where Si/Al << 1.5, is a consequence of Loewenstein's rule, which imposes the alternation of Al and Si in tetrahedral sites. Tetranatrolite, where Si/Al > or = 1.5, is interpreted as the dehydration product of paranatrolite, whose high H (sub 2) O content and complete disorder in tetrahedral sites is attributed to an unusual genesis (high T and PH (sub 2) O). Accordingly, a definition of natrolite, gonnardite, tetranatrolite and paranatrolite is suggested.

ISSN: 0935-1221
Serial Title: European Journal of Mineralogy
Serial Volume: 7
Serial Issue: 3
Title: Order-disorder in natrolite-group minerals
Affiliation: Universita di Ferrara, Istituto di Mineralogia, Ferrara, Italy
Pages: 501-508
Published: 199506
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 36
Accession Number: 1995-041694
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables
N36°45'00" - N38°15'00", E12°00'00" - E15°00'00"
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 199515
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