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Quadridavyne, [(Na,K) (sub 6) Cl (sub 2) ] [(Ca (sub 2) Cl (sub 2) ] [Si (sub 6) Al (sub 6) O (sub 24) ], a new feldspathoid mineral from Vesuvius area

Elena Bonaccorsi, Stefano Merlino, Paolo Orlandi, Marco Pasero and Giovanna Vezzalini
Quadridavyne, [(Na,K) (sub 6) Cl (sub 2) ] [(Ca (sub 2) Cl (sub 2) ] [Si (sub 6) Al (sub 6) O (sub 24) ], a new feldspathoid mineral from Vesuvius area
European Journal of Mineralogy (August 1994) 6 (4): 481-487

Abstract

Quadridavyne was found at Ottaviano, near Naples, within ashes of the 1906 volcanic activity of Vesuvius. It occurs as transparent, colourless, prismatic crystals, elongated [001] with hexagonal outline; (1<$E 1 back 40 up 40 ->00) twinning is common; H. approximately 5, D 2.335, D (sub calc) 2.354 g/cm (super 3) ; Omega 1.529, epsilon 1.532, EPMA results gave SiO (sub 2) 33.09, Al (sub 2) O (sub 3) 27.62, CaO 11.35, Na (sub 2) O 11.21, K (sub 2) O 5.93, SO (sub 3) 1.08, Cl 12.13, less Cl = O 2.74, = 99.67, leading to the ideal formula (calculated on the basis of the number of tetrahedral cations, because of the undefined crystal-chemical role of the SO (super 2-) (sub 4 ) anion) of [(Na,K) (sub 6) Cl (sub 2) ][Ca (sub 2) Cl (sub 2) ][Si (sub 6) Al (sub 6) O (sub 24) ] where the square brackets successively include the chemical content of channels, cages and framework. Indexed XRD powder data are tabulated; strongest lines 3.71(vS), 3.31(vS), 4.85(S), 2.788(S) Aa; a 25.771, c 5.371 Aa; Z = 4, space group P6 (sub 3) /m. The structure of quadridavyne is topologically identical to that of davyne; the major difference lies in the long-range ordering of the alkali ions (Na (super +) and K (super +) ) and Cl (super -) within the open channel along [001], resulting in the doubling of the a parameter.


ISSN: 0935-1221
Serial Title: European Journal of Mineralogy
Serial Volume: 6
Serial Issue: 4
Title: Quadridavyne, [(Na,K) (sub 6) Cl (sub 2) ] [(Ca (sub 2) Cl (sub 2) ] [Si (sub 6) Al (sub 6) O (sub 24) ], a new feldspathoid mineral from Vesuvius area
Affiliation: Universita di Pisa, Dipartimento di Scienze della Terra, Pisa, Italy
Pages: 481-487
Published: 199408
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 13
Accession Number: 1995-001806
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: 3 tables
N40°49'00" - N40°49'00", E14°25'60" - E14°25'60"
Secondary Affiliation: Universita di Modena, ITA, Italy
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 199501
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