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How rare is it for Amethysts to have 3 way pleochroism?

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this is a ceylonese amethyst not heated or treated in anyway other than native cut and set. photo taken inside in natural daylight at midday in the southern hemisphere.

asked Jul 27, 2016 by Blacksorrento (120 points)
edited Jul 27, 2016 by Blacksorrento

1 Answer

0 votes
Amethyst should not be pleochromic - it is a monochromatic gemstone. If it is indeed exhibiting strong pleochroism perhaps your gemstone is iolite, not amethyst.
answered Sep 18, 2016 by hershel (49,730 points)
Thank you for your answer hershel.
As far as I know it has been assayed definitely as an Amethyst. The stone was evaluated and its RI and SG fell within Amethysts parameters. Having said that though, I am only going on what the certified gemologist told me. They said it showed a strong pleochroism of blue, violet and red.  I have tried to research this and found out that Amethysts are as you said non pleochromic, hence the reason I asked the question in the first place.  3 people in the fine jewellery trade have told me it is a most unusual stone. As a lay person, how does one simply test for pleochromic tendancies? I have photographed this stone on many occasions, it is a chameleon. it can display itself being indigo blue, raspberry red, magenta and violet depending on what natural daylight it is in. I have even seen it totally pink but have not been able to capture that on camera.