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Crystal chemistry of danalite from Daba Shabeli Complex (N Somalia)

Published online by Cambridge University Press:  05 July 2018

P. Nimis ,
G. Molin  and
D. Visonà
P. Nimis
Affiliation:
Dipartimento di Mineralogia e Petrologia, Università di Padova, Corso Garibaldi 37, 1-35122 Padua, Italy
G. Molin
Affiliation:
Dipartimento di Mineralogia e Petrologia, Università di Padova, Corso Garibaldi 37, 1-35122 Padua, Italy
D. Visonà
Affiliation:
Dipartimento di Mineralogia e Petrologia, Università di Padova, Corso Garibaldi 37, 1-35122 Padua, Italy
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Extract

Danalite is the Fe2+ end-member of the minerals of the helvite group, which have the general formula M8(BeSiO4)6S2, with M = (Mn,Fe2+,Zn). These minerals are relatively uncommon, although limited amounts are known at many localities round the world (e.g. Ragu, 1994; Larsen, 1988; Kwak and Jackson, 1986, and references therein). Their typical host rocks are skams, but occurrences in mineralized veins pegmatites, and altered alkali granites have also been reported. Danalite is rarer than helvite (Mn endmember) and genthelvite (Zn end-member) and, unlike the other two end-members, has never been found nor synthesized as a pure mineral (Mel'nikov et al., 1968).

Keywords

danaliteDaba Shabeli ComplexSomaliacrystal chemistry
Type
Short Communications
Information
Mineralogical Magazine , Volume 60 , Issue 399 , April 1996 , pp. 375 - 379
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1996

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