Scratched Pearls...can they be fixed?

[Caitlin]

Rumors about some related procedure used specifically to darken pearls have been dismissed 'round here as bogus. And I have yet to find any substantial report elsewhere anyway.

I am having trouble understanding what you did mean..... what procedure and what is being dismissed as bogus about it?

 

[Valeria101]

I am having trouble understanding what you did mean.....

Two things:

#1. that no reports of irradiating pearls to darken them (or to achieve any other commercially desirable effect) have been reported o this forum - as far as I know. And rummors of uch treatments have been disissed.

#2. that I could not find reports saying otherwise elsewhere.

All in all, nothing covert: I thought that the GIA article would contribute towards answering the question whether irradiating pearls does anything to them. Whether such effects ave been or could be used for commercial purposes, no idea whatsoever. Would be curious to hear more too.

 

[Caitlin]

Sounds like we have material for a couple of new threads......

 

[Josh]

More than ten years ago I remember hearing about radioactive freshwater pearls that would make a geiger counter jump all over the place. It was my understanding that nuking was what made the color of those freshwater pearls look like exagerated Tahitians. Have I been living a lie? Some one set me straight please.

 

[jshepherd]

More than ten years ago I remember hearing about radioactive freshwater pearls that would make a Geiger counter jump all over the place. It was my understanding that nuking was what made the color of those freshwater pearls look like exaggerated Tahitians. Have I been living a lie? Some one set me straight please.

Let's try to set the record straight. It sounds like you have heard a story that has an element of truth, but has been passed down too many times to remain intact.

Irradiation does exist. I say "does" very lightly, however, as it was an old practice in Japan, started in the 1960s and continued into the 70s and 80s, but never on a large scale.

The irradiation is done with gamma rays, and only changes one type of mother of pearl - freshwater. It affects the manganese which darkens the MOP. Manganese is only present in freshwater mussel shell, not marine mollusk.

So how does it darken cultured pearls?

With akoya, the bead is darkened, not the nacre. So the color change is actually the bead showing through the nacre. The nacre is still white and translucent, but appears to be dark.

This will not work with South Sea pearls, as the nacre is too thick, not Tahitian pearls for obvious reasons.

With freshwater pearls, composed solidly of mussel nacre, the nacre will darken and typically gray. The longer the gamma radiation lasts, the darker the pearls will become. This was almost exclusively a Japanese practice, however, and more or ended with the Japanese freshwater pearl industry.

There is no radiation danger from treated pearls. That part of what you heard, Josh, was an "old pearler's tale". Referring to Strack "There is no danger that the pearls themselves will emit radiation as a result of the treatment, as the radioactive base element cobalt 60 produces the stable daughter element nickel 60".

 

[Josh]

Cool, thanks Jeremy. I had to read it twice but will go to bed less stupid tonight. But wait a minute, does that explain the wild colors too?

 

[CortezPearls]

Hi Knotty and Caitlin. Yeah, pearls die from excessive heat. They lose their color, luster and orient. Fifteen years ago on one our first harvests we buffed a few with a polishing wheel. They died months later and looked hideous. I don't know the temperature that needs to be respected but I can tell you that they became too hot to hold in your hand.
Skinning is not hard but you have to go VERY slowly. I could tell you how but then I'd have to change my name, get a nose job and send my family into hiding.

I agree with Josh! And here is a picture to prove it...a "dead dyed FWP". I was conducting some of my torture tests (FWPs make excellent Guinea pigs) and the heating test produced some of the ugliest results: after some 10 days, the pearls produced some "sub-cutaneous" bubbles and they started peeling in parts...nacre was "flaking".

The original pearls looked nice (photo included also) before subjected to the "Heat Tests".

 

[Caitlin]

Commercial grade black dyed FW pearls often have chips and chunks missing like that. Strack said in her lecture that the black dye makes them more brittle....

 

[CortezPearls]

Cool, thanks Jeremy. I had to read it twice but will go to bed less stupid tonight. But wait a minute, does that explain the wild colors too?

I would also like to have an answer to this question. My information sources told me that some dyes used in China contain oil-based substances and /or metallo-porphyrins. But I do not have any certainty...

 

[Josh]

So... no answer out there? Us natural pearl farmers want to know.

 

[jshepherd]

From what I have seen the dyes are mainly organic based. But each factory has a proprietary mix of chemicals and dyes that they use. It all starts with little bags of colored powder and a labs worth of equipment. Some do a better job than others. I have never found one, however, that does a perfect job all the time.

 

[knotty panda]

Irradiation: Isn't the post office using irradiation and isn't there a concern of the effects on gemstones, although I haven't heard of the effects on pearls specifically.

 

[Slraep]

For the most part, the more valuable coloured gemstones need an extremely intense source of nuking and lengthy time in the tube for producing lasting colour effects. In other words, the electrons have to get really hot and bothered in order for a lasting colour change change to occur. I'm not sure the post office is using such power or nuking for more than a few seconds. I sure hope not! I'm guessing they use your averge X-ray in order to detect metals and maybe a different type of irradiation for certain foods before they are either sent out of the country or coming in. Food irradiation is making someone in government a whole lot of money while further devitalizing our food supply.

I don't think the postal nuking affects pearls in any way, except maybe if they were infested with live insects, fungi, mold or bacteria(???). Too bad the government can't figure out how to get rid of heavy metals instead.

Slraep

 

[3rd pearl]

nuked pearls

nuked pearls

Many years ago pearls were irradiated as the early attempts to make "off color" and "off lustre" pearls more sell-able, create new colors, more demand. There have been many more processes discovered that do a safer/better job of it, so irradiating pearls has sort of gone by the wayside.

 

[Josh]

cheating

cheating

OK, thanks everyone. Shouldn't dyed pearls be considered second rate to beautifully occuring natural ones? Am I alone in thinking it is sort of dirty and cheating? Am I gonna make a lot of people mad with that question?

 

[Valeria101]

[dyed pearls be considered second rate] Am I gonna make a lot of people mad with that question?

Not here... I wouldn't thin so. The case for untreated pearls has been made over and over on this forum.

Shops such as Pearl Paradise and Cortez Pearls even came up with untreated pearls to follow the enthusiasm for pristine pearls (non-exhaustive list).

Treatments remain accepted too.

'Place for everyone.


At least this is the image I go from the months I've been hanging around.

 

[Josh]

Alright, thanks Valeria101. My French side got the better of me. Just trying to start an argument, like at the dinner table.

 

[Valeria101]

Hm.... if you would have proposed to consider treated pearls 'better', that would have started quite some conversation, I'd bet!

 

[Slraep]

OK, thanks everyone. Shouldn't dyed pearls be considered second rate to beautifully occuring natural ones? Am I alone in thinking it is sort of dirty and cheating? Am I gonna make a lot of people mad with that question?

Way. No way. No way, dude.

Slraep

 

[pernula]

OK, thanks everyone. Shouldn't dyed pearls be considered second rate to beautifully occuring natural ones? Am I alone in thinking it is sort of dirty and cheating? Am I gonna make a lot of people mad with that question?

I personally prefer untreated pearls. But I would like to know on what basis you call dyed pearls "dirty and cheating" ? They are very strong and judgmental words.

Thanks,
Pernula