Advertisement

The Submicroscopic Structure of Wenkite

Abstract

Wenkite (after Prof. E. Wenk) is an alumosilicate mineral which was named and found by Papageorgakis (1962) in highly metamorphosed calcitic marbles of the Ivrea zone. The structure determined by H.-R. Wenk (1973) yielded the formula Ba4(Ca9.1,Na0.9)6(Al0.4Si0.6)20O39(OH)2(SO4)3. Wenkite has a true trigonal symmetry of P31m and a pseudohexagonal symmetry of P6-ٙ2m (a 0 = 13.515 Å, c 0 = 7.465 Å). It has an interrupted [SiO4]—[AlO4] framework with hexagonal building units similar to that of the zeolites cancrinite and gmelinite. The structure refinement revealed partial occupancy of certain lattice sites in the mineral, suggesting that wenkite may possess a domain structure due to growth twins, submicroscopic twins or antiphase domains.

Keywords

Superlattice Reflection Antiphase Domain Extra Reflection Calcitic Marble Growth Twin 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Busing, W.R., Martin, K.O., Levy, H.A.: A Fortran crystallographic function and error program. ORNL-TM-305 (1962).Google Scholar
  2. Lee, F.: The submicroscopic structure of wenkite, a transmission electron microscopy study. M.S. Thesis, University of California, Berkeley (1973, unpubl).Google Scholar
  3. McLaren, A.C., Phakey, P.P.: A transmission electron microscope study of amethyst and citrine. Austr. J. Phys. 18, 135–141 (1965).CrossRefGoogle Scholar
  4. Papageorgakis, J.: Wenkit, ein neues Mineral von Candoglia. Schweiz. Mineral. Petrog. Mitt. 42, 269–274(1962).Google Scholar
  5. Radcliffe, S.V., Heuer, A.H., Fisher, R.M., Christie, J.M., Griggs, D.T.: High-voltage (800 kV) electron petrography of the type B rock from Apollo 11. Proc. Apollo 11 Lunar Sci. Conf. Geochim. Cosmochim. Acta, Suppl. 1, 1, 731–748 (1970).Google Scholar
  6. Wenk, H.-R.: The structure of wenkite. Z. Krist. 137, 113–126 (1973).CrossRefGoogle Scholar
  7. Wenk, H.-R., Lee, F.: Wenkite, an interrupted framework silicate with domain structure (abs.). Geol. Soc. Am. Abst. with Progr. 4, 7, 703–704 (1972).Google Scholar

Copyright information

© Springer-Verlag Berlin · Heidelberg 1976

Authors and Affiliations

  • F. Lee

There are no affiliations available

Personalised recommendations