January 24 Through February 4—TUCSON, ARIZONA: Annual show
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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Wed Sep 28, 2022 3:05 pm 
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Please excuse the terrible photos in the album - it's hard to get the colour change to show up correctly in pictures.

https://imgur.com/a/Rvxwloq

The first photo is with a 2700K LED flashlight, the second is with a 5000K LED flashlight. In real life, the yellow light really does look exactly like that - very red-pink. For the second photo, though, the stone is definitely less purple and more blue in real life.

As for definitive chemical testing, I don't believe I've heard of anyone sending this off for things like LIBS or LA-ICP. But I can take this piece to Tucson this year and see what people think :)


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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Wed Sep 28, 2022 4:21 pm 
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Does anyone think that if a stone were faceted from this type of quartz material and submitted to a lab for gem identification, that it may be given a color-change or color-shifting call?

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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Wed Sep 28, 2022 7:06 pm 
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All intensely colored amethyst does this to some extent in my experience, as do rhodolites approaching this color range or pretty much anything in this magneta-purple-blue color range. This phenomenon seems to be occasionally/cyclically noticed and used in marketing.
The zoning phenomenon (which can look like zones of almost pure blue) can be seen in nigerian amethyst as well. I suspect it is partially zoning and partially twinning since intensely colored amethyst is also pleochroic between reddish purple and violet blue, so it could just be a zone oriented favorable to blue amongst zines oriented favorable to red-purple. As I recall they did seem to swap around eith different orientations but I was plating with this material a while back.
There is a distinct violet-blue color phenomenon evident in multi-treated quartz from some mines in brazil ('blueberry quartz') which might play a role. I don't know if that material has been thoroughly studied.

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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Fri Sep 30, 2022 12:11 pm 
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sorry.. HERE is the LINK to the Video

https://www.dropbox.com/s/ckaa441gpa079 ... 2.mp4?dl=0


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