Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-05T08:55:39.963Z Has data issue: false hasContentIssue false
  • English
  • Français

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
Get access Rights & Permissions [Opens in a new window]

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

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Burt, M.D. (1980) The stability of danalite, Fe4Be3(SiO4)3S. Amer. Minerals, 65, 355–60.Google Scholar
Hassan, L., and Grundy, H.D. (1985) The crystal structures of helvite group minerals, (Mn,Fe,Zn)8- (BeeSi6O24)S2- Amer. Mineral. t, 70, 186–92.Google Scholar
Holloway, W.M. Jr., Giordah, T.J. and Peacor, D.R. (1972) Refinement of the crystal structure of helvite, Mn4(BeSi04)3S. Acta Crystallogr., B28, 114—7.Google Scholar
International Tables for X-ray Crystallography (1974) Ibers, J.A. and Hamilton, W.C. (Eds.), vol. 4, pp. 99—101, Kynoch Press, Birmingham.Google Scholar
Ishihara, S. (1977) The magnetite-series and ilmenite- series granitic rocks. Mining GeoL, 27, 293—305.Google Scholar
Kwak, T.A.P. and Jackson, P.G. (1986) The compositional variation and genesis of danalite in Sn-F-W skarns, NW Tasmania, Australia. Neues Jahrb. Mineral., Mh.t, 452—62.Google Scholar
Larsen, A.O. (1988) Helvite group minerals from syenite pegmatites in the Oslo Region, Norway. Contribution to the mineralogy of Norway, No 68. Norsk. Geol. Tidsskrift, 68, 119–24.Google Scholar
Mel'nikov, O.K., Litvin, B.M. and Fedosova, S.P. (1968) Production of helvite-group compounds [in Russian]. In: GidrotermaVnyi Sintez Kristallov,(Lobachev, A.M., ed.). pp. 167—74, Nauka Press, Moscow (quoted in Burt, 1980).Google Scholar
Ottolini, L., Bottazzi, P. and Vannucci, R. (1993) Quantification of lithium, beryllium, and boron in silicates by Secondary Ion Mass Spectrometry using conventional energy filtering. Anal. Chem., 65, 1960–8.CrossRefGoogle Scholar
Pauling, L. (1930) The structure of sodalite and helvite. Zeit Krist., 74, 213–25.Google Scholar
Ragu, A. (1994) Helvite from the French Pyrenees as evidence for granite-related hydrothermal activity. Can. Mineral., 32, 111–20.Google Scholar
Shannon, R.D. (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallogr.y A32, 251—5.Google Scholar
Tokonami, M. (1965) Atomic scattering factors for O2-. Acta Crystallogr., 16, 486.CrossRefGoogle Scholar
Visona, D. (1993) The Daba Shabeli gabbro-syenite complex: an element of the gabbro belt in the Northern Somali basement. In: Geology and mineral resources of Somalia and surrounding regions.(E. Abbate, M. Sagri and F.P. Sassi, eds.) Bull. 1st. Agronom. Oltremare, special issue, 113 A, 59—82, Firenze.Google Scholar
Zachariasen, W.H. (1963) The secondary extinction correction. Acta Crystallogr., 16, 1139–44.CrossRefGoogle Scholar