Hostname: page-component-77c89778f8-sh8wx Total loading time: 0 Render date: 2024-07-23T23:24:43.814Z Has data issue: false hasContentIssue false
  • English
  • Français

Origin of optical pleochroism in orthopyroxenes

Published online by Cambridge University Press:  14 March 2018

Roger G. Burns
Roger G. Burns*
Affiliation:
Department of Mineralogy and Petrology, University of Cambridge, Cambridge
Get access Rights & Permissions [Opens in a new window]

Summary

The necessary conditions for optical pleochroism in orthopyroxenes are: ordering of Fe2+ ions, with preferential occupation of M2 positions; presence of small, high-valence cations (Al3+, Fe3+, Ti4+) in M1 positions; replacement of Si by Al; and a sufficient Fe2+ content. These factors favour an intensification of the charge-transfer absorption bands in the ultra-violet that is more marked for the α vibration direction than for β and γ. This leads to absorption in the blue and a red colour in transmitted α-polarized light, while β and γ, remain green.

Type
Research Article
Information
Mineralogical magazine and journal of the Mineralogical Society , Volume 35 , Issue 273 , March 1966 , pp. 715 - 719
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1966

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

Burns, (R. G.), 1965. Ph.D. Diss., Univ. of California, Berkeley.Google Scholar
Burns, (R. G.), 1966. Journ. Sci. Instr., vol. 43, pp. 58-60.Google Scholar
Byström, (A.), 1943. Ber. deut. keram. Gesell., vol. 24, pp. 2-15.Google Scholar
Ghose, (S.), 1962. Amer. Min., vol. 47, pp. 388-94.Google Scholar
Ghose, (S.), 1965. Zeits. Krist., vol. 122, pp. 81-99.Google Scholar
Howie, (R. A.), 1963. Min. Soc. Amer., Spec. Pap. no. 1, pp. 213-22.Google Scholar
Ingham, (K.), 1957. M.Sc. Thesis, Univ. of Manchester.Google Scholar
Orgel, (L. E.), 1960. An Introduction to Transition-Metal Chemistry: Ligand-Field Theory. Methuen and Co., Ltd., London. 180 pp.Google Scholar
Warren, (B. E.) and Modell, (D. I.), 1930. Zeits. Krist., vol. 75, pp. 1-14.Google Scholar