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Stoppaniite, (Fe,Al,Mg) (sub 4) (Be (sub 6) Si (sub 12) O (sub 36) )*(H (sub 2) O) (sub 2) (Na,) a new mineral of the beryl group from Latium (Italy)

Giancarlo Della Ventura, Paolo Rossi, Gian Carlo Parodi, Annibale Mottana, Mati Raudsepp and Mauro Prencipe
Stoppaniite, (Fe,Al,Mg) (sub 4) (Be (sub 6) Si (sub 12) O (sub 36) )*(H (sub 2) O) (sub 2) (Na,) a new mineral of the beryl group from Latium (Italy)
European Journal of Mineralogy (February 2000) 12 (1): 121-127


Stoppaniite was found at Capranica, in the Vico volcanic complex, where it occurs inside the miarolitic cavities of a volcanic ejectum as very rare, transparent, light blue, hexagonal-prismatic crystals < or = 0.5 mm in length; it is associated with biotite, quartz, sanidine, hematite, danburite, helvite, hellandite and allanite-Ce). It shows a weak pleochroism from colourless to very light blue; epsilon 1.619, omega 1.625; D 2.79 g/cm (super 3) . EPMA results are presented for the iron-rich core (stoppaniite) and for an (Fe,Al)-rich rim (beryl); for stoppaniite, the composition can be expressed by the formula (Fe (super 3+) ) (sub 3) (Mg,Fe (super 2+) )Na(Be (sub 6) Si (sub 12) O (sub 36) ).2H (sub 2) O, or ideally Fe (super 3+) (sub 4) Be (sub 6) Si (sub 12) O (sub 36) . Indexed XRD powder data are tabulated; strongest lines 3.278(vS), 8.12(s), 2.903(S), 4.00(m), 2.553(mw), 1.752(mw) Aa; a 9.397, c 9.202 Aa, V 703.7 Aa (super 3) ; space group P6/mcc. The crystal structure has been described earlier. A rational classification of beryl group minerals is proposed, based on octahedral site occupancy, i.e. Al (beryl), Fe (super 3+) (stoppaniite) and Sc (bazzite).

ISSN: 0935-1221
Serial Title: European Journal of Mineralogy
Serial Volume: 12
Serial Issue: 1
Title: Stoppaniite, (Fe,Al,Mg) (sub 4) (Be (sub 6) Si (sub 12) O (sub 36) )*(H (sub 2) O) (sub 2) (Na,) a new mineral of the beryl group from Latium (Italy)
Affiliation: Universita di Roma Tre, Dipartimento di Scienze Geologiche, Rome, Italy
Pages: 121-127
Published: 200002
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 23
Accession Number: 2000-027048
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables
N41°13'60" - N42°49'60", E11°30'00" - E14°00'00"
Secondary Affiliation: CNRS-UPRESA, FRA, FranceUniversity of British Columbia, CAN, CanadaUniversita di Torino, 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: 200009
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