tahitian pearl treatment

[London pearler]

Hi,

Does anyone know which types of treatments are currently being used on Tahitian pearls?

 

[Pearl Dreams]

Tahitian pearls are not treated, as a whole.

The exceptions are chocolate pearls, which are color treated, and some pistachio pearls that were identified as color treated by the GIA-- see this article:

https://www.gia.edu/gems-gemology/s...lored-pearls-treated-ballerina-pearl-company?

 

[pattye]

PD, interesting about the pistachio pearls, perhaps they are still considered less valuable than the desirable peacock, but certainly have come into their own in popularity. A relief to know GIA does thorough a investigation on these treatments.

 

[BlackPearlDudeDC]

I loved that the GIA used "Hair Bleach" Powder during their experiments.

The first necklace in the pic looks too matchy...not to say years of collection naturally colored pearls wouldn't produce the near same results.

Thanks PD for sharing the link. I remember this article it was good to read it again.

 

[jshepherd]

I wouldn't say Tahitian pearls aren't treated. For the most part they aren't, except as mentioned above. But there are companies in China that coat, heat and color Tahitians that might otherwise be considered unsaleable. There is one company called Shanghai Pearl that exhibits at most of the shows in Hong Kong and they typically have baskets and baskets strands that are treated junk.

 

[MSC]

I wouldn't say Tahitian pearls aren't treated. For the most part they aren't, except as mentioned above. But there are companies in China that coat, heat and color Tahitians that might otherwise be considered unsaleable. There is one company called Shanghai Pearl that exhibits at most of the shows in Hong Kong and they typically have baskets and baskets strands that are treated junk.

Is this the same Shanghai Pearl that sells natural pearls or are those two different companies?

 

[jshepherd]

No, this company (based in Hong Kong) does not sell natural pearls.

 

[Pearl Dreams]

... there are companies in China that coat, heat and color Tahitians that might otherwise be considered unsaleable. There is one company called Shanghai Pearl that exhibits at most of the shows in Hong Kong and they typically have baskets and baskets strands that are treated junk.

Well, that is dismaying! I wonder where those pearls end up being sold? And if there is any way a buyer can recognize them for what they are?

Also, Jeremy, I have a question. A pearl-loving friend bought some Tahitians that she says smell bad...manure-like. But these aren't gas pearls or souffles-- she emailed me photos and they just looked like regular baroque Tahitians. What could make Tahitians smell that way, and what should she do to fix the problem, short of returning them? Are there treatments that could have made them smell bad?

 

[jshepherd]

Well, that is dismaying! I wonder where those pearls end up being sold? And if there is any way a buyer can recognize them for what they are?

Also, Jeremy, I have a question. A pearl-loving friend bought some Tahitians that she says smell bad...manure-like. But these aren't gas pearls or souffles-- she emailed me photos and they just looked like regular baroque Tahitians. What could make Tahitians smell that way, and what should she do to fix the problem, short of returning them? Are there treatments that could have made them smell bad?

A lot of times they appear to have micro-cracks all over them. I've seen coated ones too that you can prick with a needle.

The smell you're describing happens with circled pearls sometimes. It's terrible when you get an entire lot drilled and one of those pearls is in the mix and the factory doesn't remove it. You'll know as soon as you open the box. It's similar to a gas pearl and the same concept, but not typically filled with gaseous liquid to the same extent.

 

[Pearl Dreams]

How should I advise my friend? Return the pearls? Clean them-- with what?

They were drilled and strung! I wonder how the (normally reliable) vendor missed the smell.

 

[jshepherd]

How should I advise my friend? Return the pearls? Clean them-- with what?

They were drilled and strung! I wonder how the (normally reliable) vendor missed the smell.

They can be washed or left out in fresh air. The smell will eventually go away. But they should definitely come off the string. They should not have been knotted with that smell present.

 

[Pearl Dreams]

Thanks Jeremy. I will tell her.

 

[London pearler]

I hear there has been a large increase in the price of Tahitians recently, is this correct?
Was this down to a poor harvest, pollution problems, or some other reason and is it affecting all sizes?

 

[Marianne]

Stringing material just soaks up "that nasty smell" from small bits of organic matter left in the blank spaces of some baroque pearls that becomes um... liberated with drilling. Sometimes it is really hard to tell which pearl on a strand is the stinker. They need to be separated, washed, thoroughly dried, then sniffed.

 

[Cees]

true, the price of Tahiti pearls under 10 mm has gone up a lot in auctions due to higher demand from China. Golden smaller South Sea have gone down due to a higher production.

The smell should be treated by the pearl wholesaler, I have seen here in Bangkok a process to preserve the pearls because the smelling substance can change the colour of the pearls near the drilling holes.

 

[Pearl Dreams]

I will pass this information along, Marianne and Cees, thanks.

As far as washing the pearls, what should she wash them with? The usual we recommend (mild soap and water), or what?
Is one bath likely to suffice or should she expect to have to wash them repeatedly or wait a long time for the smell to dissipate?
I don't know what to recommend to her as I've never experienced this myself (thankfully!)

She is in her rather brief return period and I'm thinking she may prefer to just send them back to her seller if it looks like she will have a hard time removing the smell.

 

[Marianne]

The sell really should have addressed the odor issue.
As previously stated, the organic matter inside the pearl is what smells bad ( I call it sea silage ). Sometimes it is liquid and spills over some or all of the pearls in a strand or hank rendering them odoriferous. Most of the pearls will be just fine, but the offenders need to be identified and dealt with. I have found this mostly with larger kasha and baroque SSs. To clean out the yuck, I inject the pearl with half strength H2O2 (using an insulin syringe) and let it foam out onto a paper towel then rinse inside and out with clear water and repeat till no more brown bits come out. Then lay shake, blow out the excess water and lay on towel till totally dry inside which may take up to a week. Sometimes will need to repeat the process if still stinky after dry...
Cees is right about color change too. I had a beautiful large blue free form baroque that turned a pure white after cleaning out the yuck which totally makes sense in that the blue color comes from interior fouling and not the nacre itself. Seems as if this should not be an issue with Tahitians though.
At any rate, I think the seller should make this right!

 

[Pearl Dreams]

Thanks Marianne...I am passing it on. The buyer will have to decide what she wants to do about it. It would make sense for her to send it back and ask the seller to fix the problem.

 

[ericw]

In my own experience (I have worked a time with ichtyologists and marine biologists), the only way to fix a bit this problem of the decomposition of water organisms' matter, is a long bath in formalin, thus that's a way to avoid, definitively, because formalin is extremely hazardous. And even after this long bath in formalin, the organic matter keeps a bit of bad smell, as long as it can take some moisture inside. Then, there are no reasonable issues to fix that, especially in case of circle pearls smelling bad, because there's a high organic matter concentration in the back of their paths, which are always in local moisture.
Edit: maybe salt concentration makes the difference between circle pearls smelling bad or not, because salt catches more moisture. Thus, it might be interesting to bath pearls several times in pure waters to remove salt as far as possible, fist...?

 

[ericw]

The smell should be treated by the pearl wholesaler, I have seen here in Bangkok a process to preserve the pearls because the smelling substance can change the colour of the pearls near the drilling holes.

To explain what you are talking of, Cees, Pearl Dreams and Marianne, this phenomenon of colour change looks like most happening when reducing environment, of any decaying organic matters, turns to oxydizing environment, when this matter is removed.
Edit: after some research, maybe polarization of metallic ions can change the nacre colour, but also the organic structure of pigments, all changing when environment turns to oxydizing one. That's well known in case of any colour indicator used in chemical analysis, for exemple.