Treatment of White South Sea Pearl

[CLICLASP]

Thank you Jeremy for reminding us that fantastic post.

[Caitlin]

So maeshori includes tumbling polishes? Or do the Paspaleys do other types of maeshori?

[jshepherd]

No. One would never polish pearls before treating them. Polishing would not be a pre-treatment, it would be done post-treatment.
Edit: Unless it was done to prepare the pearls for auction. After the pearls are sold at auction, (to almost exclusively Japanese processors) they will go through maeshori and then again polishing.

[Caitlin]

That is what I thought. So,the pearls Paspaley keeps are just tumbled, but they ones that go to Japan go through Maeshori? I am just getting more confused, because when I went to the other thread, they showed the Paspaley Pearls being tumbled. What did I miss?

[jshepherd]

You didn't miss anything. The link was in response to Rusty's post.

Soaking in oils, tumbling in walnut or corn husks or meashori is "tampering with the evidence" or "stretching the truth". However, if, in a real fancy way you tell the person you did it to bring out the true inner beauty of the pearl that mankind would have been denied the opportunity to see had you not done so, well good luck to you.

Treatment, puts our industry in line with the used car trade.

I mean no offence, but please understand that as a pearl farmer, when people "treat" pearls to change their grade, I'm offended.

It is easy to disparage what other people do, but my point is that almost always something is being done. Paspaley is polishing the pearls with oil-infused walnut shell in that photo and calling it "washing." Even the producers who do absolutely nothing to their pearls know full well that when they sell them (hama-age lots), nearly all of them are going to go through some sort of processing if they go through Japan. Even the finest pearls will at least go through some sort of polishing.

[lisa c]

Besides, the nature of what's doing the polishing matters. Crushed walnut shells are really rather benign compared with something like a gem-slurry or the like. Crushed nut shells are used in skin scrubs/exfolliants. So, how could it be considered as anything other than a slight buffer? Do I have that right?

[jshepherd]

It still "brings out the inner beauty of the pearl." When you exfoliate, you are doing the same thing in a way. But pearl polishing in this fashion is not meant to remove and layers.

IMHO, after a strand has been drilled and worked, it should definitely be polished. The pearls have been stuck to a stick pad, have pearl dust stuck in the microscopic crevices, and have been handled extensively. They don't need to go on a polishing wheel, but corn or walnut will make them shine.

[lisa c]

Thanks for sharing info so patiently.

That's about what I figured. If it's safe for human skin it wouldn't do anything much to a pearl's surface, aside from cleaning and I like the analogy to buffing one's nails.

[Lagoon Island Pearls]

Technically, anything that prepares a pearl for market are post harvest "treatments". Salt slurry scrubbing, drying and oiling included.

In all of my naturals, blisters and cultured pearls, drying is where I draw the line. Table salt etches the surface of pearls and contains chlorine... which is an oxidizer and sodium... which is a metal.

Sea salt contains even more elements:

Element Relative concentration (by mass) [%]
Chloride (Cl-) 55.03
Sodium (Na+) 30.59
Sulfate (SO42-) 7.68
Magnesium (Mg2+) 3.68
Calcium (Ca2+) 1.18
Potassium (K+) 1.11
Bicarbonate (HCO3-) 0.41
Bromide (Br-) 0.19
Borate (BO33-) 0.08
Strontium (Sr2+) 0.04
Miscellaneous constituents 0.01

Ana has asked me about my post harvest treatments in the past, presumably because any foreign agents applied to pearls will skew the spectrum analysis of SEM. Protein (especially once dried) sticks to aragonite like poop to a wool blanket. She often notes, it's very difficult to break a shell or pearl to obtain a clean, entire crystal.

Merely because most cultured pearls will never see the inside of a lab does not mean they are exempt from correct terminology. There are way to many abused terms in pearling and we ought not perpetuate them needlessly.

I'm with R&B on this one. IMHO, cultured pearls that are never intended to be scientifically analyzed and treated in a wet slurry of salt by non-mechanical means (ie) manually can be deemed as cleaned and "untreated" or minimally treated. Pearls treated with any other agent or thermal control without disclosure are cheating the grade system.

[jshepherd]

Opinion is just that and why we are here. We have many that do have the more purist view on these things and they can be debated, but nothing is going to change within the industry, especially given the amount of secrecy involved in everything from maeshori, bleaching and even in some cases polishing. Within the industry, from many producers, wholesaler, retailers, to even a lot of consumers, many of our opinions would be viewed as the fringe.

From the time only natural pearls ruled the world, treatments and processing were a part of business and were not often discussed. Pearls were bleached in bottles of water left in the sun. Natural pearls were often, and still are, sold with the most invasive treatment of all (peeling), and yet it is not routinely disclosed.

I submit that if anyone posting in this thread was a processor in Japan, they would follow the same protocol that is their industry standard.

[Lagoon Island Pearls]

We have many that do have the more purist view on these things and they can be debated, but nothing is going to change within the industry, especially given the amount of secrecy involved in everything from maeshori, bleaching and even in some cases polishing. Within the industry, from many producers, wholesaler, retailers, to even a lot of consumers, many of our opinions would be viewed as the fringe.

By that same logic Jeremey, adding melamine to baby formula and cat food to thwart the protein level grading system would be perfectly acceptable, but you and I both know it's wrong on all levels.

Although treating pearls is not a health issue, how is this any different?

[jshepherd]

So since it's ok to kill a mosquito that bites you, it's perfectly acceptable to shoot a human that hits you? Logic can be twisted in any way.

[Caitlin]

Within the industry, from many producers, wholesaler, retailers, to even a lot of consumers, many of our opinions would be viewed as the fringe.

Don't you mean the avant garde? There is actuallly a range of authority with a range of opinions here. In the rebellion against chemical fertilizers and pesticides, I remember how long we had to search for organic produce and now, it is at the Safeway. And all their generic frozen and canned foods are organic too.

Bleaching was done by the sun, but not to change the color from cream to white as a rule. of course, since they would be in a jar of water in the gulf sun, they are heat treated too.


I gotta get that pearl book about the Persian Gulf.

[jshepherd]

Bleaching by the sun is one of many treatments to naturals, and makes it no more of a natural treatment than many others. Remember the Papyrus Graecus Holmiensis from nearly 2,000 years ago recommending feeding pearls to Chickens? In India the pearl doctors would put pearls in alcohol and then dry them in direct heat to stop the conchioline from swelling up - very similar to one now common type of maeshori.

[Caitlin]

This is truly one of the greater pearl mysteries, but as long as we talk about it here, someone is talking about it.