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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Wed Jan 21, 2015 7:32 pm 
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I personally do not consider color "Shift" gems to be as rare as a true shift from hue to hue.

ImageBut, as the result of a lightning strike?


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PostPosted: Wed Jan 21, 2015 10:23 pm 
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lembeckgems wrote:
we also sold the flame fusion synthetic birthstones. the stuff Golay and Dalloz were manufacturing for the syn. birthstone trade.

the 12 months were made from syn. spinel, syn. corundum, and spinel corundum doublets or soudees (soldered).

the syn. corundum "alex" was unmistakably syn. looks more like the Madagascar cc Garnet than Alex. too blue.

the corundum used for Amethyst was either too navy blue zoned or was to pink overall. dalloz exported the pink variety packaged under the name 'kunzite' but it was used for the Feb birthstone.

we tried making a corundum, spinel February doublet. Sanoir in Switzerland made it for us. It was purple without any blue but it looked more like the old purple tourmaline than Amethyst.

Nicky. Amazon Joe D and I just got some rough in. don't know if that's of interest to you. mentioned the Amethyst material you got to Joe of course since i speak with him every day. is the material dark? I think he mentioned that what he's seen is darkish.

Nice to read the old posts by Steve Lembeck.

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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Thu Jan 22, 2015 7:41 am 
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Barbra Voltaire wrote:
Quote:
I personally do not consider color "Shift" gems to be as rare as a true shift from hue to hue.

ImageBut, as the result of a lightning strike?


Please explain, i may be out of touch with color changing stones due to lightning or mis reading your comment.

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 Post subject: Re: Amethyst colour turns to blue - fact - but what DO I hav
PostPosted: Thu Jan 22, 2015 1:14 pm 
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I'm referring to this post:
yanakie wrote:
Years ago my mother gave me an amethyst 'crystal ball' - I think it must be man made as it has bubbles inside.
A few weeks ago I noticed it had turned blue during an electrical storm. Yesterday we had another electrical storm, so I checked it, and it had once again it had turned blue. The colour changed as I moved through different locations... anything from a pale transulcent greyish-blue to tourquise blue. In another location it became a more rose coloured amethyst.
Attachment:
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Attachment:
globe2.jpg

I have more photos... I am so confused as to what is going on.
I am wondering if a combination of static energy and light frequencies has some effect on this object
If anyone can give me some idea of what this is made of I would be grateful... I can't believe it has taken me over 40 years to notice this happening...


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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Thu Jan 22, 2015 4:47 pm 
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I wonder if it is the same ball we see from one picture to the other ?
The bubbles don't seem to be located quite in the same place inside.
Maybe it's just a false impression I get but...


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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Sun Mar 18, 2018 2:14 pm 
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Hello everyone. Well, I have an old brooch made by one of the first jewellery companies in Australia (it is around 100 years old) ... I don’t know if it is made of amethyst but I thought it was because when I realised it changes colour in different lighting I looked up colour changing gemstone and the only reference I could find was to colour changing amethyst. In normal indoor lighting it is a pinkish purple colour but if you shine a torch on it or take it outside or place it near a fluorescent light it changes to a brilliant bright blue colour ... it is not a different shade of the same colour but a completely different colour ... if not amethyst what could it be?


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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Sun Mar 18, 2018 9:37 pm 
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If I had to guess, this piece looks like costume jewelry, typical mid-century.
I suspect the stones are foil backed glass with fluorescent properties....aka rhinestones.

The piece is seriously dirty. Don't use any liquids, but you could brush off the stones with a very soft brush and then rub with a microfiber cloth.

Not amethyst.

PLEASE NOTE. I HAD TO REFORMAT THESE PICS BECAUSE THEY WERE UPLOADED AT 4300px.

AT THE TOP OF THE PAGE THEIR IS A HEADER READING
"PLEASE KEEP ALL POSTED PICTURES, DIAGRAMS, etc. TO A MAX OF 600px. Larger graphics distort our pages. Thanks!"


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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Tue Sep 27, 2022 10:19 am 
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Here's an Amethyst (untreated) that was part of a much larger parcel I acquired from a pal in the industry
( see video)


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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Tue Sep 27, 2022 1:18 pm 
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CPOL wrote:
Here's an Amethyst (untreated) that was part of a much larger parcel I acquired from a pal in the industry
( see video)

? No video link.

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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Tue Sep 27, 2022 2:17 pm 
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For a short while there was production of very strongly color shifting Amethyst from a deposit in Rwanda. In daylight/LED it strongly resembled the velvety blue-Purple color associated with Tanzanite. In incandescent light it shifted to a reddish-Purple color like a fine Amethyst. It is the strongest color shifting Amethyst material I have personally seen. An interesting thing is that the color shifting occurred in zones in the same piece of stone. Orientation for Dichroism also had an affect on the strength of the shift. To get the most effect you needed to cut the stone from within the color shifting zone, and orientate it properly. Then it was dramatic. As the mine developed the Amethyst produced no longer had this characteristic. The production eventually turned to Amethyst with an unattractive dull brown/grey component that was undesirable, and didn't sell well.


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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Tue Sep 27, 2022 5:39 pm 
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Curios. Do you have any links to this original material?


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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Tue Sep 27, 2022 6:59 pm 
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Barbara,

Here is a link to a video where the color shift is shown at the start of the video. You will see in all the other stones how dichroic it is. It was really remarkable stuff.

I still have a couple of kilos of the original production squirreled away in my safe. Not selling it for now anyway.

Steve

https://www.youtube.com/watch?v=4fvgF_m3uFw&t=24s

Another video that shows the strength of the color shift in various parts.

https://www.moregems.com/blogs/news/rwa ... 171c&_ss=r

MoreGems want a pretty high price for the stuff, and is mostly sold out.


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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Wed Sep 28, 2022 12:12 am 
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Never heard of any quartz being graded with a color-shift designation from the GIA on a gem identification report. That being said I most diffently am not the foremost expert in the field, and truthfully Amethyst would not make my list for a report in any case.

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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Wed Sep 28, 2022 12:52 am 
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1bwana1 wrote:
For a short while there was production of very strongly color shifting Amethyst from a deposit in Rwanda. In daylight/LED it strongly resembled the velvety blue-Purple color associated with Tanzanite. In incandescent light it shifted to a reddish-Purple color like a fine Amethyst. It is the strongest color shifting Amethyst material I have personally seen. An interesting thing is that the color shifting occurred in zones in the same piece of stone. Orientation for Dichroism also had an affect on the strength of the shift. To get the most effect you needed to cut the stone from within the color shifting zone, and orientate it properly. Then it was dramatic. As the mine developed the Amethyst produced no longer had this characteristic. The production eventually turned to Amethyst with an unattractive dull brown/grey component that was undesirable, and didn't sell well.

OH! I totally forgot about this material - got a fist-sized chunk from Rex Guo a couple of years ago and still have it sitting in my rough collection. There were two veils in it and I never got around to sawing it...

Barbra - this stuff is NUTS. It really did look like purplish-blue tanzanite shifting to almost a purplish rhodolite.


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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Wed Sep 28, 2022 1:01 pm 
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OK....I trust you both, Arya and Steve. Neither of you are given to hyperbolic exaggerations.

My first reaction to the video was going to be a cheap shot pointing to the the color changing hand holding the amethyst. But I will refrain.

I suspect something unusual must be present in the chemistry of this material.
Has anyone, to your knowledge, tested the stuff with LIBS?


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