Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-27T22:57:38.263Z Has data issue: false hasContentIssue false
  • English
  • Français

Effenbergerite, BaCu[Si4O10], a new mineral from the Kalahari Manganese Field, South Africa: description and crystal structure

Published online by Cambridge University Press:  05 July 2018

G. Giester  and
B. Rieck
G. Giester
Affiliation:
Institut für Mineralogie und Kristallographie, Universität Wien, Dr. Karl Lueger-Ring 1, A-1010 Wien, Austria
B. Rieck
Affiliation:
Institut für Mineralogie und Kristallographie, Universität Wien, Dr. Karl Lueger-Ring 1, A-1010 Wien, Austria
Get access Rights & Permissions [Opens in a new window]

Abstract

Effenbergerite, ideally BaCu[Si4O10], structure determined by single crystal X-ray methods in space group P4/ncc, a = 7.442(2)Å, c = 16.133(5)Å, V = 893.50 Å3 Z = 4, is a new mineral from the Wessels mine, Kalahari Manganese Field, South Africa. It is associated with native copper, calcite, quartz and clinozoisite within pectolite veinlets, embedded in a matrix of braunite, sugilite and hausmannite. Effenbergerite occurs as transparent blue platelets with perfect cleavage parallel to {001} in sizes up to 8.0 × 8.0 × 0.1mm. It has a pale blue streak, subconchoidal fracture, a calculated density of 3.52gcm−3 and an estimated Mohs' hardness of 4–5. Effenbergerite is uniaxial negative with ω = 1.633(2), ε = 1.593(2), strongly pleochroic from intense blue (ω) to nearly colourless (ε). The strongest lines in the X-ray powder diffraction pattern (with refined lattice parameters a = 7.440(1)Å, c = 16.133(2)Å) are: (dobs/Iobs/hkl) (8.0624/100/002), (4.0325/39/004), (3.5443/29/104), (3.1998/44/114), (2.6892/21/006), (2.3943/41/116), (2.0169/34/008), (1.9466/22/108) and (1.4802/21/2.0.70).

Effenbergerite is the natural analogue to synthetic BaCu[Si4O10], isotypic with SrCu[Si4O10] and CaCr[Si4O10] as well as with the minerals cuprorivaite, CaCu[Si4O10] and gillespite, BaFe[Si4O10]. The structure consists of silicate sheets [Si8O20]8− parallel (001) formed by corner-linkage of silicate 4-membered rings. The copper(II) atom is nearly planar 4-coordinated; the barium atom has a distorted cubelike environment of oxygen atoms. The mineral is named for Dr. Herta S. Effenberger of the University of Vienna, Austria.

Keywords

effenbergeriteBaCu[Si4O10]barium copper silicatenew mineralcrystal structureKalahari Manganese FieldSouth Africa
Type
Mineralogy
Information
Mineralogical Magazine , Volume 58 , Issue 393 , December 1994 , pp. 663 - 670
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1994

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

Belsky, H.L., Rossman, G.R., Prewitt, C.T. and Gasparik, T. (1984) Crystal structure and optical spectroscopy (300 to 2200 nm) of CaCrSi4Oi0 . Amer. Mineral., 69, 771–6.Google Scholar
Chakoumakos, B.C., Fernandez-Baca, J.A. and Boatner, L.A. (1993) Refinement of the Structures of the Layer Silicates MCuSi4Oio (M = Ca,Sr,Ba) by Rietveld Analysis of Neutron Powder Diffraction Data. J. Solid State Chem., 103, 105–13.CrossRefGoogle Scholar
Dixon, R.D. (1985) Sugilite and associated minerals from the Wessels mine, Kalahari Manganese field. Trans. Geol. Soc. South Africa., 88, 11–17.Google Scholar
Dixon, R.D. (1986) Metamorphism in the Kalahari Manganese field. Geocongress ‘86 Extended Abstracts; Geol. Soc. South Africa, 505-8.Google Scholar
Dowty, E. (1993) ATOMS 2.3 a Computer Program for Displaying Atomic Structures, Kingsport, TN.Google Scholar
Hazen, R.M. and Burnham, C.W. (1974) The crystal structures of gillespite I and II: a structure determination at high pressure. Amer. Mineral., 59, 1166–76.Google Scholar
Hazen, R.M. and Finger, L.W. (1983) High-pressure and high-temperature crystallographic study of the gillespite I-II phase transition. Amer. Mineral., 68, 595–603.Google Scholar
Janczak, J. and Kubiak, R. (1992) Refinement of the Structure of Barium Copper Silicate BaCu[Si4O10] at 300K. Ada Crystallogr., C48, 1299–1301.Google Scholar
Kleyenstuber, A.S.E. (1984) The mineralogy of the manganese bearing Hotazel formation of the Proterozoic Transvaal sequence of Griqualand West, South Africa. Trans. Geol. Soc. South Africa, 87, 267–75.Google Scholar
Lambert, U. (1988) Kristallchemie von Cu(I) und Cu(II) in oxidischer Bindung. Heidelberger Geo-wiss. Abh., 18.Google Scholar
Liebau, F. (1985) Structural Chemistry of Silicates. Structure, Bonding and Classification. Springer-Verlag Berlin Heidelberg New York Tokyo.CrossRefGoogle Scholar
Lin, H.C., Liao, F.L. and Wang, S.L. (1992) Structure of BaCuSi4O10 . Ada Crystallogr., C48, 1297–9.Google Scholar
Mandarino, J.A. (1981) The Gladstone-Dale rela-tionship: Part IV. The compatibility concept and its application. Canad. Mineral., 70, 441–50.Google Scholar
Mighell, A.D., Hubbard, C.R. and Stalick, J.K. (1981) NBS*AIDS83. A FORTRAN Program for Crystallographic Data Evaluation, NBS Technical Note 1141.Google Scholar
Nicolini, L. and Porta, P. (1970) Preparation, X-ray and magnetic investigations of some silicates containing transition metal ions. Gazetta chimica Italiana, 100/79, 923–30.Google Scholar
Pabst, A. (1959) Structures of some tetragonal sheet silicates. Ada Crystallogr., 12, 733–9.CrossRefGoogle Scholar
Sheldrick, G.M. (1993) SHELXL-93 Program for Crystal Structure Refinement, Univ. Gottingen, GermanyGoogle Scholar
Von Bezing, K.L., Dixon, R.D., Pohl D. and Cavallo G. (1991) The Kalahari Manganese field, an update. Mineral. Record, 22, 279–97.Google Scholar
Wilson, A.J.C. (ed.) (1992): International Tables for Crystallography, Vol. C, Kluwer Academic Publishers, Dordrecht.Google Scholar