Pearls and Lab Reports

[Bogus]

Hi...
(I'm new to this subject, so sorry if this has been covered before..)

I was looking at a couple of lab reports (one AGTA, the other GIA) and found them a bit lacking in info, especially GIA. Do the pearl pros here agree? Is this a problem? Do you care?

In the GIA report I saw, they only said "natural pearl", and didn't specify whether or not it was salt or fresh water. Is this odd?

And what about enhancements? I found an AGTA rpt that said "no evidence of color enhancement", but the strand in question was multicolored. I saw no comments about enhancement in reports on white-ish pearls.

Can't white-ish, cream colored pears be treated, enhanced too?

And one more question... I saw a couple of reports identifying "natural" freshwater pearls. How do they know this for sure since FWPs don't have beads in them?

Thanks!!
Bogus

 

[Zeide Erskine]

Hi Bogus,

Although I agree that the reports should state what type of pearl it is, value-wise it makes not very much difference whether the pearls are saltwater or freshwater with a definite bias in favor of freshwaters as a lot more natural saltwater pearls are being harvested than freshwater ones and freshwater pearls are usually of higher quality.

When the report states that no evidence of color enhancement could be found that should apply equally to white and cream pearls as to fancy color pearls.

Freshwater pearls that occur naturally tend to have a much less pronounced ring pattern than cultured ones because of their lower conchiolin content. One can determine that through sacrificing (cutting random samples in half) and in cat scans. Regular radiology is usually not up to the task. There are some freshwater cultured pearls with beads in them that regular radiology can readily detect. The trend is going toward bead nucleation as that gives big round pearls fast as Kokichi Mikimoto concluded in 1909 when he switched to Mise-Nishikawa.

Zeide

 

[preswine]

GIA is the most well respected lab and, for many, the only acceptable certification. However, they seem to do the least extensive testing and have the longest turn around time. Perhaps their limited scope identification is more conclusive or perhaps they can just afford to be lazy and let their reputation carry them.

Regarding the detection of enhancements, I believe this usually requires tests other than the standard X-ray (and GIA only does the standard X-ray). Lesser known labs seem to offer more testing and more complete reports. However, keep in mind that pearl testing is usually billed as pearl "identification" and they are usually just that. Here is a list of labs that do Pearl testing:
American Gem Trade Association (AGTA)
European Gemological Laboratory (EGL)
Gemological Institute of America (GIA)
International Gemological Institute (IGI)

Lastly, although tissue cultured do not have beads in them, they do retain a remnant of the tissue, which can be seen in the X-ray. I've also heard that the growth pattern of the nacre as seen in the X-ray can be used to distinguish between tissue cultured and naturals.

 

[Bogus]

Thanks, Zeide!

The trend is going toward bead nucleation as that gives big round pearls fast as Kokichi Mikimoto concluded in 1909 when he switched to Mise-Nishikawa.

Well, this is news to me. The ONLY thing I thought I knew about pearls (before joining this forum ) was that FWP were always tissue nucleated...now it appears that that is wrong!

My goodness.
Bogus

 

[preswine]

Although I agree that the reports should state what type of pearl it is, value-wise it makes not very much difference whether the pearls are saltwater or freshwater with a definite bias in favor of freshwaters as a lot more natural saltwater pearls are being harvested than freshwater ones and freshwater pearls are usually of higher quality.

You mean in the context of naturals right? Because I thought the conventional wisdom with cultured pearls was that saltwater pearls are generally higher quality than freshwater. Hence the big stir over the freshadamas.

 

[jshepherd]

That would be average aethetic quality, not actual. That is the typical trade-off.

 

[preswine]

That would be average aethetic quality, not actual. That is the typical trade-off.

Are you saying that the highest quality FWP achieve a higher quality than the highest quality SWP, despite the average quality FWP being lower quality than the average quality SWP?

 

[jshepherd]

Absolutely, that is is true. But top quality CFWP are much more rare, and they are rarely ever made into strands. They will not have the metallic reflection of the Akoya, but will have orient which the Akoya lack. Orient is much more rare than an enhanced metallic shine.

But, typically Akoya are more aesthetically pleasing (to most) than the average freshwater. This is due to shape, inclusions, and luster. Akoya are almost always round, inclusions are very difficult to see (in high quality), and the luster tends to 'pop'.

 

[Zeide Erskine]

Hi,

The average quality of freshwater cultured pearls in terms of nacre thickness, luster, and orient at harvest is higher than that of saltwater cultured pearls. The saltwater cultured pearls, however, are predominantly bead nucleated which gives them a whole extra surface to take enhancement, i.e. the bead surface and the nacre skin surface. As a result, they are not only more round (which is a new standard for pearl aesthetics, in Tavernier's time symmetry was good enough or at least a pleasing and interesting baroque) and can be enhanced in more ways and at more levels. Of course, you also have to figure in that the saltwater perliculture industry has all the marketing clout to perpetuate in the media what they think people should want in a pearl which usually comes out in their favor.

In untreated natural pearls, freshwaters win hands down anytime in any pearl beauty competition and have done so since the dawn of man. Hence the Romans called freshwater pearls "unio" (the one and only) and saltwater pearls "margarita" (the ordinary pearl). Native American and Asian cultures also put a clear emphasis on freshwater pearls. This is probably due to the fact that freshwater pearls have about 6 times the manganese content of saltwater pearls and manganese makes pearls glow in the dark. There are a few exceptions to this otherwise infallible rule. The estuary pearls harvested in the Ganges river delta, and pearls harvested on the coast of one Korean island also have very high manganese content and thus glow in the dark.

Zeide

 

[KAC]

In regards to round natural pearls

which is a new standard for pearl aesthetics, in Tavernier's time symmetry was good enough or at least a pleasing and interesting baroque

A little off topic but I find this hard to understand, I mean if symmetry was a key value factor then wouldn't a round pearl have perfect symmetry and thus be more desirable?

 

[Bogus]

Are large, roundish, top-of-the-line FWPs usually tissue nucleated or bead nucleated?

Bogus

 

[Zeide Erskine]

Hi Bogus,

Currently about 80% of the large rounds are still tissue nucleated and only 20% of them bead nucleated. That is changing however in favor of the beaders. As soon as the bead nucleated freshwater pearls reach market majority they will probably cut down culturing time to get more and rounder rounds. At that time I will probably have to get my own farming operations up and running again or invest in farms that tissue nucleate marine pearls.

Zeide

 

[Bogus]

Thanks for your patience with my questions, ZE (may I call you that? )

I didn't even know there was such a thing as 10+mm round FWPs until I found this site! (Typical of me...I'm beginning to think I desperately need a strand..LOL)

I know...or thought I knew, anyway...that the quality of a cultured pearl depended on the size of the bead, or put another way, the thickness of its nacre.

Is this true of the big roundish FWPs, too? How big are the beads used to grow them?

Thanks...
Bogus

 

[jshepherd]

Wait, those figures are way off from mine. The bead-nucleated freshwater trade is much less than even 1% in freshwater. They are being marketed as "fire balls" and "free forms". You do not have to worry about the large rounds being bead nucleated. I have never come across any with a bead. This bead-nucleation is a relatively new thing in the large farms of Zhuji. It is increasing, but only because the prices of those 'tailed' pearls are being artificially inflated with romantic names and mixed South Sea strands.
If you get Modern Jeweler check out the latest issue. It has a report that quotes Fuji Voll and myself about the growth of the industry and has pictures of a strand as well.

 

[Zeide Erskine]

Hi Jeremy,

The production of the bead nucleated freshwater pearls (with about 35% coin pearls and 65% rounds) was 4-5t in 2001 and was projected to reach 30t (that's metric tons or 1000kg) by the end of 2005. If you consider the amount of truely round tissue-nucleated pearls, you see that 65% of 30t corresponds to about 20t or 20% of total output in fine rounds (estimated at 100t). I posted the name of company before but here I go again: Chenghai Xinxi Pearl Culturing Factory and Guangdong Hin Qing Pearl Culturing Company JV, Technical Director: Xie Shao He. I do not know whether these pearls are always declared to be nucleated (except for the obvious case of coin pearls), but they probably put out even more than that considering the lively franchise business.

Zeide

 

[Zeide Erskine]

Hi Bogus,

The largest nuclei used in Chenghai are 17mm and will get a 2mm or so absolute cultivation (that means nacre thickness measured from the radius) for a grand total of a 21mm final pearl. These round pearls are almost exclusively sold to Hong Kong dealers and heaven knows what they will be declared to be. The typical nucleus size is only 9-10mm, though. The Chenghai operation is getting their rounds already very round most of the time. The new franchisees in Zheijiang still have tail problems. The Chengai growers are using a hybrid mussel but I do not know exactly what went into that particular genetic mix. A sizeable share of their output are yellow goldens and have already been found mixed in with golden South Sea strands. These pearls are by no means cheap. So, you are not getting cheated by having any of these mixed in with your South Sea cultured pearls. Actually you are getting a substantially better value due to their greater nacre thickness.

Zeide

 

[jshepherd]

Prejoected, yes, but they did not produce rounds. To date, no farms have perfected rounds with a bead. The GIA tested this back in 2004, sampling thousands of rounds because comsumers were hearing rumors, based on the earlier plans. But they did not find a single round with a nucleus. I have never seen one either. Those that claim to be producing rounds are very, few and farm between. Certainly not accounting for any percentage of total production.
On the ground in Zhejiang they have said it is because of the incision. It does not heal fast enough, and the mantle secretes into it - they all have some sort of tail. This is why you could buy them cheap just a couple of years ago. Now they are trying to make money on their investments by artificially inflating prices with the help of HK pearl houses like Rio, and selling them with fancy names and descriptions at the shows.

 

[Zeide Erskine]

Hi Jeremy,

It seems that Elisabeth Strack got enough rounds without a tail to photograph and show in her 2001 book. Fred Ward also seems to have found some and so does Antionette Matlins. The real difference is that these pearls are not marketed in China but in Hong Kong and Japan where they are being sold as Kasumigauras and South Seas depending on color. I consider them a better deal than South Seas and definitely on a par with Kasumigauras but nowhere near a tissue-nucleated round from Zheijiang or Heilongjian.

Zeide

 

[Bogus]

Oh, dear...I'm afraid a lot of this is going over my layperson head!

Actually I've become interested in big freshwater pearls...not South Seas. When I said 'big' I was thinking 10-11mm.

Perhaps I should explain myself a bit. My first love is natural, untreated/heated gemstones. Until I found this website, I've never been too interested in cultured pearls because I've always thought of them as 'nacre coated beads".

Since natural pearls out of my league, I'm intrigued with these "big" FWPs.

I'm still having trouble picturing how these bigger roundish FWPs can be grown from a small irregular "tissue" nucleus. What is the "tissue"? Is it round? Does it come in different sizes?

Thanks.
Bogus

 

[KAC]

The mantle tissue used is just a small piece of tissue and they can place up to 50 in a mussel at one time. Most of the resulting pearls do not come out round or even close to round, but the sheer numbers of freshwater pearls produced makes round freshwater pearls possible.