Origin of optical pleochroism in orthopyroxenes
- 14 March 1966
- journal article
- Published by Mineralogical Society in Mineralogical Magazine and Journal of the Mineralogical Society
- Vol. 35 (273) , 715-719
- https://doi.org/10.1180/minmag.1966.035.273.06
Abstract
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.Keywords
This publication has 2 references indexed in Scilit:
- Apparatus for measuring polarized absorption spectra of small crystalsJournal of Scientific Instruments, 1966
- Mg2+– Fe2+order in an orthopyroxene, Mg0.93Fe1.07Si2O6Zeitschrift für Kristallographie, 1965