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Dichroic cordierite
https://www.gemologyonline.com/Forum/phpBB2/viewtopic.php?f=20&t=23327
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Author:  danco [ Sat Dec 03, 2016 10:05 pm ]
Post subject:  Dichroic cordierite

From Madagascar
http://www.mindat.org/photo-578762.html
Image
http://www.mindat.org/photo-578763.html
Image

Author:  dchallener [ Mon Dec 05, 2016 11:08 pm ]
Post subject:  Re: Dichroic cordierite

I thought iolite was always dichroic? Is there a form that is not?

Author:  Stephen Challener [ Mon Dec 05, 2016 11:27 pm ]
Post subject:  Re: Dichroic cordierite

Colorless :D

Author:  cascaillou [ Tue Dec 06, 2016 12:54 pm ]
Post subject:  Re: Dichroic cordierite

As a biaxial stone, coloured cordierite has pleochroism of trichroic type (= 3 distinct colors of pleochroism, depending on orientation)
Blue cordierite also shows polychroism (= intense pleochroism easily seen with the naked eye in non-polarized light)

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