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 Post subject: Can you know a mildly toned cyan tourmaline is cuprian?
PostPosted: Fri Aug 19, 2016 1:48 pm 
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Paraiba tourmaline and its ilk has produced a lot of interest in one of the great families of gemstones that comes in all the colors of the rainbow and more. As prices have risen, people who had no reason to appreciate tourmaline, must now try and satisfy the elite gem collectors with their expertise and exceptional gemstones. This can be a dangerous path, for as they say, a little bit of information can be more dangerous than none at all.

In my wanderings on the inter net, I found an old, established, family run jewellery store. As I read about their experience with estate jewellery, colored stones, hand engravers and other areas of the trade, the store came on as very supportive and knowledgeable. I had found them because I was looking for news about paraiba tourmaline and the store had aready had a bad experience with heating paraiba/cuprian tourmaline. After sending it to Germany and waiting months the rich reddish purple stone came back almost colorless instead of the hope for cyan brilliance. And with its flaws glaring the stone was in essence worthless.

Now by this time you are probably wondering what this post has to do with its title. Well the next tourmaline item I read about on this store's site was a ring made from a mildly toned and moderately saturated, blue green paraiba/cuprian tourmaline. Or at least the store thought it was a paraiba/cuprian tourmaline. They had not had it tested!!!!!! And their principle concern was whether is was from Brazil or Africa because of the difference in valuation. They chose the less expensive values, which is fine, I guess for a stone that could easily not be copper bearing at all.

MANY GRADES OF COPPER BEARING TOURMALINE CAN NOT BE SEPARATED FROM IRON BEARING TOURMALINE OF THE SAME COLOR BY EYE. AND IRON CAN PRODUCE THE SAME COLOR AS COPPER IN SOME TOURMALINE.

This is why the Harmonization Group came up with the classification, of paraibe-like tourmaline. The best of the paraiba-like material comes out of Afghanistan/Pakistan and it is beautiful and valuable, but no where as valued as Paraiba or its cuprian family in the same range of colors. The long time dealer that own some of the stones asked me to use my spectrometer on them, because some clients of his found it unbelievable that they did not contain copper. Well there was no sign of copper in them and no gemological laboratory has ever found a significant amount of copper in any tourmaline from Afghanistan/Pakistan. (If I was buying a tourmaline in the limited range of paraiba colors that I saw at that dealers, I would buy the iron colored material, it is both very beautiful and much more affordable.)

So, does higher grades of paraiba/cuprian merit their high prices? I think so, but it is not only based on their color. It is also based on their vividness and a glow-like quality that produces an outstanding visual presence. The stone in the fine handmade ring that was proported to be paraiba from Africa did not appear to have that presence. Now it could be cuprian, but it can not be determined to be that, without testing.

It would be tragic if a fine family establishment that has catered to the needs of the public for many years should run a ground on the rock of tourmaline ignorance. Please do not buy any tourmaline that is proported to have copper, as a chromophore/coloring agent without a laboratory report. l just sent in one of my stones to the GIA to be tested. I am confident, from my spectrometery work that it is cuprian. But I could not ask the going price for a flawless 2 carat, purplish oval if it is cuprian, without confirmation from a gemological laboratory, in writting, of its cuprian nature.

Bruce

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 Post subject: Re: Can you know a mildly toned cyan tourmaline is cuprian?
PostPosted: Fri Aug 19, 2016 10:22 pm 
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No offense, Bruce, but this seems like a roundabout way to say "I found a jeweler who doesn't know much about tourmaline, or who doesn't care much about getting it right." The thing is, most jewelers don't know much about gems of any kind, and it's not uncommon for them to not care that they don't know. Especially, perhaps, when not knowing the difference might lead to a higher price. You're preaching to the choir here.

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 Post subject: Re: Can you know a mildly toned cyan tourmaline is cuprian?
PostPosted: Sat Aug 20, 2016 8:56 am 
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No offense take and I bet the choir is better by being preached to occasionally.

If I had needed to look for a jeweller that was both ignorant of and indifferent to quality in tourmaline I would not have to search the internet. I worked with a home grown case for some years. He was enthralled by putting 20 dollar pillow cut (to mask the numerous flaws) stones into custom made jewellery and getting a good price for them. Such is life.

No, the fellow I found on the internet was cut from different cloth. He offered services such as arranging for color stones to be auctioned and searching for exceptional gemstones as request by his clients. And I don't mean just bringing in a lot on consignment from normal commercial outlets.

The two things that really stood out with this story is that the jeweller had the stone recut by what looks like a custom cutter and that the big question in his mind was whether it was an African stone of Brazilion stone, not whether it was copper bearing or not.

It is pleasing to think that the people of Gemology Online are well versed in the uniqueness or lack of it in the colors of Paraiba/cuprian tourmaline. It is not well supported in the material I have read.

Bruce


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 Post subject: Re: Can you know a mildly toned cyan tourmaline is cuprian?
PostPosted: Sat Aug 20, 2016 8:35 pm 
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Doesn't Paraiba-type suffer from similar metamorphic alterations as emerald?
If so, then even the characteristic glow might not be enough to label it as cuprian, just tiny flaws and inclusions...

Trying to heat such a material sounds like a good way to get expensive purple tourmaline to crumble, and Afghanistan has plenty of mint tourmalines for those that want brilliant cyan ones.


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 Post subject: Re: Can you know a mildly toned cyan tourmaline is cuprian?
PostPosted: Sat Aug 20, 2016 8:58 pm 
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Paraiba tourmaline was formed in a pegmatite as was the African material so I think you need to use a different term for its abundant flaws. Whether the glow like qualities come from inclusions or the physical properties of material and its interaction with the mind/eye is perhaps in doubt with some stones, but either way, the glow like property is not definitive for having copper. Iron colored tourmaline, such as the cyan ones you mentioned or top quality sea foam can also glow. I don't think that any gemstone can match top grade Paraiba in its beauty, but not everything out there is top grade or even close to it. And after heating the pretty little Paraibas can fall a part in the setting.

Bruce


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