July 21-28—ARDEN, NORTH CAROLINA: 16th Annual Western North Carolina Rockhound Roundup; Mountain Area Gem and Mineral Association; Camp Stephens, daily 8:30-5
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 Post subject: Dichroic cordierite
PostPosted: Sat Dec 03, 2016 10:05 pm 
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From Madagascar
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 Post subject: Re: Dichroic cordierite
PostPosted: Mon Dec 05, 2016 11:08 pm 
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I thought iolite was always dichroic? Is there a form that is not?


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 Post subject: Re: Dichroic cordierite
PostPosted: Mon Dec 05, 2016 11:27 pm 
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Colorless :D

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 Post subject: Re: Dichroic cordierite
PostPosted: Tue Dec 06, 2016 12:54 pm 
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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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