Post subject: Most likely ID for gem that changes colour.
Posted: Wed May 05, 2021 8:21 am
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Joined: Tue Feb 07, 2017 8:33 pm Posts: 7
Hi everyone, and thanks in advance for your knowledge. I sell gold and silver jewellery in Australia and recently came upon a 14k Russian gold ring that had what I thought was an amethyst... only when I examined it under my loupe that has a florescent light, it turned a green/blue colour. I've realised now that the purple shade changes too, depending on the lighting. Under more yellow lighting it is a richer, darker shade of purple, and under whiter lighting it is a much paler purple. So far I've only noticed it go green when I have the abovementioned loupe light directly on it, but will experiment more tomorrow (it's night here in Australia). It's never happened with other stones I have, so definitely isn't the loupe light doing weird things.
From what I've googled alexandrite usually changes in the other direction - green to purple. The stone also appears to be quite soft, as I can see wear to the facets under the 15x loupe. I believe it to be a natural gemstone (not glass or synthetic).
Any ideas? Fluorite? Colour changing garnet? Open to help and advice, Thanks.
Post subject: Re: Most likely ID for gem that changes colour.
Posted: Fri May 07, 2021 12:51 pm
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Joined: Tue Apr 05, 2016 7:58 pm Posts: 1424 Location: San Marcos, CA
Yes and in that thread I called it Amethyst, but here we start at a maybe Fluorite. MillyMolly why do you believe it is a natural? Prong abrasion to a gemstone would not automatically make it a softer gem material. We have a lot gems of harder classes of gems show abrasion mostly due to loose setting, and possibly the stone already had the abrasion and was reset. The list goes on as to why. I agree with Barbra, need a picture and without an image it is like that phone call we get everyday where all there is a vague interpretation of values and Google searching to go by. For a true I'd take it to a qualified individual for proper testing. Like Barbra.
When you say "most likely ID for gem that changes color" the answer is almost always vanadium doped synthetic sapphire. Far from the only option, but by far the most probable. Large color changing stones are expensive (with the possible exception of fluorite which is more moderately priced) so they don't tend to be separated from their provenance so easily (and color change fluorite is enough of a collector's stone that it is also unlikely to end up mixed with other things, and soft enough to be unlikely to survive if it did). In comparison there are tons and tons of synthetic cc sapphires which were sold decades ago, often mislabeled as alexandrite, and they pop up everywhere.
Post subject: Re: Most likely ID for gem that changes colour.
Posted: Fri Aug 27, 2021 10:31 pm
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Joined: Tue Feb 07, 2017 8:33 pm Posts: 7
Sorry for late reply - life got in the way. For those that answered, thanks so much. It has been confirmed as alexandrite. Being set in antique russian gold (the home of alexandrite) it is going to be taken to a gemologist company for further checks and a professional valuation (unfortunately they are in a lockdown zone due to covid, coupled with a few month long waiting list, hence this still being on hold)
Post subject: Re: Most likely ID for gem that changes colour.
Posted: Sat Aug 28, 2021 11:53 am
Site Admin
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Still waiting for the picture MillyMolly. Seeing the mounting would be interesting, as well as the Russian (not Soviet) hallmarking on the inside of the ring.
Post subject: Re: Most likely ID for gem that changes colour.
Posted: Sat Aug 28, 2021 8:15 pm
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Joined: Tue Feb 07, 2017 8:33 pm Posts: 7
I consulted a gemologist in a non professional setting. It is being taken to a company for the official valuation because they have more equipment and also specialise in antiques. Their valuation will be integral when I go to sell it, and will also help me decide whether I want to spend extra getting a professional to buff the stone. I have also obtained a second ring with confirmed colour changing alexandrite and am able to compare the two. The second ring is definitely likely to be synthetic due to time period, size of stone and it is UK hallmarked.
Photos are fairly pointless, as it is impossible to get the colour change unfortunately (another feature of alexandrite). I have tried multiple times with different cameras, different settings. If I put it up for sale I will have to do it via photoshop, sadly.
I have found colour changing sapphire to be challenging, but not impossible.
Context: I sell antique and vintage jewellery professionally (I'm licenced) and have gained a lot of experience through this. Will look at getting my own gemology degree soon, but at this point I am learning without it through necessity.
Post subject: Re: Most likely ID for gem that changes colour.
Posted: Sat Aug 28, 2021 9:36 pm
Site Admin
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Quote:
Context: I sell antique and vintage jewellery professionally (I'm licenced) and have gained a lot of experience through this. Will look at getting my own gemology degree soon, but at this point I am learning without it through necessity.
Another newby with attitude.
That license means you are following protocol about reporting private purchases to the proper authorities. It does not mean you are qualified as a jewellery historian, proficient in hallmarking or maker's mark identification, or someone competent to positively identify a gem.
Post subject: Re: Most likely ID for gem that changes colour.
Posted: Sat Aug 28, 2021 9:51 pm
New to the Forum or The Quiet Type
Joined: Tue Feb 07, 2017 8:33 pm Posts: 7
Barbra Voltaire, FGG wrote:
Quote:
Context: I sell antique and vintage jewellery professionally (I'm licenced) and have gained a lot of experience through this. Will look at getting my own gemology degree soon, but at this point I am learning without it through necessity.
Another newby with attitude.
That license means you are following protocol about reporting private purchases to the proper authorities. It does not mean you are qualified as a jewellery historian, proficient in hallmarking or maker's mark identification, or someone competent to positively identify a gem.
Interesting take. I guess you find a lot of people have attitude. I don't suppose it occurs to you it may be in response to your own attitude? If it is happening a lot you need to look at yourself. It would be nice if you could be more welcoming and less derisive in your responses. It may be a nice ego boost, but does not help anybody who was after help on this beginner forum.
And what you said is true enough, but I also belong to a gem and lapidary club and have handled many, many gems which gives me a lot of working experience. I think most people would agree there is some value to that.
Post subject: Re: Most likely ID for gem that changes colour.
Posted: Sat Aug 28, 2021 10:03 pm
Site Admin
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Quote:
Interesting take. I guess you find a lot of people have attitude.
Truth be told, I find the most defensive folks are the ones with the least amount of industry experience
We would be more than happy to help you if you were following our protocol. If a pic is requested, why wouldn't you just post one? Who knows, we ALL may learn something. Give it a try.
Post subject: Re: Most likely ID for gem that changes colour.
Posted: Sun Aug 29, 2021 12:37 am
Gold Member
Joined: Tue Apr 05, 2016 7:58 pm Posts: 1424 Location: San Marcos, CA
I have to agree with Barbra, it's just a picture wether it shows the precise color of changes is what many of us deal with when it comes to Color change or shifting gems and photography. Anyway all moot you clearly had other intentions requesting help here. Free being the main.
Post subject: Re: Most likely ID for gem that changes colour.
Posted: Sun Aug 29, 2021 4:39 am
Gold Member
Joined: Thu May 12, 2016 2:18 am Posts: 1542
From this thread I have no confidence in the true nature of this stone. So, I will not comment on that.
However I feel that it is important to mention that most. Gem professionals consider it unethical to use Photoshop to alter the color of a stone in images used for selling. If you do not have the necessary equipment or skills to take the required pictures hire someone who does.
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