Skip to main content
×
×
Home

An explanation of anomalous optical properties of topaz

  • Mizuhiko Akizuki (a1), Martin S. Hampar (a1) and Jack Zussman (a1)
Summary

A study has been made of topaz crystals showing a sectoral texture related to the growth of the crystal, and showing anomalous optical properties within the sectors. The growth surfaces responsible for the development of most of the sectors have been identified. The fluorine/hydroxyl sites in topaz are symmetrically equivalent in the solid crystal, but at a growth surface this equivalence may be lost, resulting in a reduction in the crystal symmetry and the ordering of fluorine and hydroxyl, the ordering scheme being retained once the crystal has formed. The reduction in symmetry expected to be produced by this ordering is in general agreement with the actual reduction in symmetry indicated by the optical properties. Heating of the topaz to about 950 °C results in the almost complete disappearance of the optical anomalies due to disordering, which may be related to the loss of hydroxyl from the crystal. Anomalous pyro- and piezoelectric phenomena may also be the result of ordering. Published optical and X-ray determinative curves for fluorine in topaz may give erroneous results for ordered topaz.

Copyright
Corresponding author
1 On leave from Institute of Mineralogy, Petrology and Economic Geology, Faculty of Science, Tohoku University, Sendai 980, Japan
References
Hide All
Adams, (F. D.) and Graham, (R. P. D.), 1926. Trans. R. Soc. Can. , Sect. IV, 20, 113-36.
Akizuki, (M.) and Sunagawa, (I.), 1978. Mineral. Mag. 42, 453-62.
Alston, (N. A.) and West, (J.), 1928. Proc. R. Soc., A, 121, 358-67. Z. KristaUogr. 69, 149-67.
Dana, (E. S.), 1892. The system of mineralogy of James Dwight Dana. Descriptive mineralogy, 6th edn. Kegan Paul, Trench, Trübner & Co. Ltd., London.
Friedel, (C.) and Curie, (J.), 1885. Bull. Soc. Minéral. France, 8, 16-27.
Greenwood, (G.), 1935. Z. Kristallogr. 91, 235-42.
Hampar, (M. S.), 1973. Ph.D. thesis, University of Manchester, England.
Hollister, (L. S.), 1970. Am. Mineral. 55, 742-66.
Hollister, (L. S.) and Gancarz, (A. J.), 1971. Ibid. 56, 959-79.
Isogami, (M.) and Sunagawa, (I.), 1975. Ibid. 60, 889-97.
Mack, (K.), 1886. Ann. Phys. Chem. (Weidemann), 28, 153-67.
Pauling, (L.), 1928. Proc. natn. Acad. Sci. USA, 14 603-6.
Phakey, (P. P.) and Horney, (R. B.), 1976. Acta Crystallogr. A32, 177-82.
Ribbe, (P. H.) and Gibbs, (G. V.), 1971. Am. Mineral. 56, 24-30.
Ribbe, (P. H.) and Rosenberg, (P. E.), 1971. Ibid. 1812-21.
Rinne, (F.), 1926. Z. Kristallogr. 63, 236-46.
Seki, (T.), 1963. Sci. Report Tohoku Univ. III. 8, 159-70.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Mineralogical Magazine
  • ISSN: 0026-461X
  • EISSN: 1471-8022
  • URL: /core/journals/mineralogical-magazine
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Metrics

Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed