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PostPosted: Thu Mar 29, 2007 3:22 pm 
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From what I know, a colour change has to be a complete change of hue under fluorescent and incandescent light. Like blue to purple or green to red. A colour change from bluish purple to pinkish purple does not qualify to be 'colour change'. I do have an Amethyst that changes from bluish purple to pinkish purple. I would call it colour shift at best.

By the way there is no need to take 2 photos to compare the colour for colour change. If the stone is deep enough, all you need is to place an incandescent source at an angle to the stone from a distance like 20cm and the stone will appear 2 different colours at 2 different sides due to the double internal reflection. If the incandescent source is at the right side of the stone, the warm colour will be seen at the left side of the stone.


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PostPosted: Fri Mar 30, 2007 11:59 pm 
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star_gem wrote:
By the way there is no need to take 2 photos to compare the colour for colour change. If the stone is deep enough, all you need is to place an incandescent source at an angle to the stone from a distance like 20cm and the stone will appear 2 different colours at 2 different sides due to the double internal reflection. If the incandescent source is at the right side of the stone, the warm colour will be seen at the left side of the stone.


Thanks for the tip, star_gem. :D

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PostPosted: Fri Apr 20, 2007 6:01 am 
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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.


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PostPosted: Sat Apr 21, 2007 9:02 pm 
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Hi Steve- The stone I recently received from the Para deposit in Brazil is dark but not overcolor. I bought a round from Joe last year at a N.Y. show and the color is similar. I am heading down to Haiti tomorrow to help some of the world's poorest people for a couple weeks. I will post the Amethyst photos when I get back.

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PostPosted: Sun May 27, 2007 12:41 am 
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I'd love to see the pics. looking forward to it. Joe says hey.


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PostPosted: Sun May 27, 2007 3:49 pm 
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Hi Steve- This is the Para -deposit Amethyst(not a great photo). Also a few shots from my Haiti trip. The conditions are beyond horrible. Makes my gem collecting seem pretty unimportant. Say hello to Joe D.
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PostPosted: Sun May 27, 2007 8:19 pm 
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I love amethyst. always have. one of my favorite stones. how many carats?


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PostPosted: Sun May 27, 2007 9:40 pm 
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Steve- Its 5.31ct.-17.3mm.x9.4mm.x7mm. Stones from this deposit are usually small. I have a nice round I got from Joe last year. I'll post a photo tomorrow.

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PostPosted: Mon May 28, 2007 11:29 am 
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Round stone from Amazon Imports. Larger pear is Para stone- note red flash.(Bottom picture and in Gem-File)

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PostPosted: Mon Nov 05, 2007 5:01 pm 
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star gem.

I know what you mean. my son has an amethyst the goes from purple / red to 100% purple blue. the chasing is complete but both hues are purple. under
some light. it looks pink. haven't been able to duplicate that.

the other thing it does. under some light it stays purple and has what I perceive as a pure blue secondary. very bright saturated blue. really pretty. so I guess it just
shifts. I'll post some pics when I get over being lazy. would like your opinion.

I have to stop posting. working all night. running on fumes. I'm looking for the post about the lack of clean cats eye tourmaline. just got some in that's way clean.
looking for that post and can't seem to stop putting my 2 cents in on other posts I come across.....


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PostPosted: Mon Nov 05, 2007 11:47 pm 
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I have several color change gems from Amethyst and Alexandrite to Sapphires. Sure all my gems have a different hue under different light but a change from green to red or from purple to pink is more than just the way it appears in the light, it is due to the reflective qualities of the stone and how that quality effects different light spectrums. There is certainly a lot of “color change” junk out there so always buy from a seller that guarantees their product with a good return policy.


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PostPosted: Tue Nov 06, 2007 2:12 am 
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thanks. my situation is not one where I have to return goods. once I buy and I'm invoiced it's done. that's the simple mechanics of the trade.

I'm just curious about nomenclature and the perspective of the business where I have some interest as a hobbyist beyond how I make a living.

I don't deal in amethyst anymore and yet it is one of my favorites. when I sell to other dealers they know as much or more about the material than I do. The only question is price. And the retailers, that's all memorandum anyway. Never had a manufacturer return anything that I can think of. It's when am I getting paid that's the
issue with some of those guys. Consequently I like selling the small manufacturers. The guys that are real jeweler / artists.

Selling a $100k order of cz to a mid size manufacturer isn't glamorous and the profit margin is tight. So, the private sales are nice as you get paid up front.

In that regard the little business I do on ebay to privates is something entirely new, with the advent of the net. I'm not used to it but I meet nice people by mostly. And collectors. I find I have to know things about gems in this new venue that I wouldn't be as concerned about on the wholesale end. And many know more or have different takes about some gems than I do. I love that. Makes my life easier and I learn something

But as far as returning goods that can't happen unless a mistake has been made. Can't remember that ever happening. Mistakes that I've made always benefit the dealer I'm selling to. lol And that has happened more than once. I could tell you a few stories. Ouch.

When I was new in the trade the first time I met Amazon Joe he came up to our office and I bought some things and some blue Topaz. Seems funny now. Blue Topaz. Anyway it turned out the Blues were synthetic!. Now those stones he did get back. And now years later we're partners so you never know where something will lead. Go figure.
partners.

Best color change I have at the moment is a gemy 3 carat cats eye ales. Perfect stone.

But the blue purple gemmy cc garnets that show up from time to time. Amazing.

In fact one parcel of Alex that I looked at had a few cc mgarnets thrown in . A real wise guy.

The whole color change thing fascinates me. Plus the fact that with certain gems the fact that they resist changing under different lighting makes them more valuable. Interesting business.

Amethyst is weakly dichroic is it not? So, I'm interested in how Amethyst reacts. Try to wrap my head around all of it but the science part is not my forte.

I did have one color change Amethyst. One in 35 years. Lousy cut. re cut and the color change dissapeared. Re cut after I sold it. What a shame. The dealer was devastated. Not good. Should have kept that one.


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 Post subject: Re: Amethyst colour turns to blue - fact - but what DO I hav
PostPosted: Wed Jan 21, 2015 6:34 am 
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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.
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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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File comment: deep amethyst
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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Wed Jan 21, 2015 2:23 pm 
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I have never personally heard of this phenomenon occurring with glass....or anything else.


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 Post subject: Re: Color change Amethyst ? Myth or fact ?
PostPosted: Wed Jan 21, 2015 6:20 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.

Example: Mali Garnet 0.33ct Yellow to Green change.


A slight shift in hue may make for a fine looking stone, but it is not a true color changing stone.


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