Pearl blemishes

[CMN]

What causes different types of pearl blemishes eg pits? Is there an authoritative source that discusses this?

 

[CortezPearls]

Hello CMN!
Excellent question...and I wish we could have an equally good answer to it.
I would be quite qualified to answer this question since I was a pearl farmer for the last...30 years? Seems like yesterday!

It all boils down to the "Pearl sac". As you know, the "pearl sac" is a sac-like group of cells that originated in -or from- the mantle's epithelial cells (those that are in direct contact with the shell). If the pearl sac has "errors", these will translate unto the pearl as flaws.

What are these errors? Unfortunately, very few people (only one, to my knowledge) have been able to "follow" the development of the pearl sac in its initial phase after pearl surgery, and at that time the technology was inadequate. At best, we can only surmise what really happens with the pearl sac. so, these errors are cause by a group of cells that might develop a malformation or just have a hormonal imbalance (hormones are essential for pearl production) and depending on the type of mantle cell errors we have is the type of flaw you will end up.

I don´t remember a source for information...since I don´t work at the Cortez Pearl farm I no longer have access to a large amount of books and articles I had. But let me look into my library and see what I can find about this subject.

 

[lisa c]

Thank you Douglas, what an excellent answer, very cool. And which mantle tissue might have the errors, the donor or the mother? Amazing science.

 

[Pearl Dreams]

The pearl sac forms from the donor tissue, so I'd expect the donor mantle would have the error.

In cultured pearls, anyway. If it's a natural pearl there is no donor, so then it would have to be the oyster's own mantle tissue.

 

[CortezPearls]

Quite correct Pearl Dreams...but not all is written in stone...or pearl, for this matter

You see, the original mantle piece might be FLAWLESS...you actually select the donor based upon this and the shell's beauty. Thing is, once it has been inserted into the body of the host oyster (or mussel) the mantle tissue starts degrading, parts of it die (sometimes all of the tissue dies) and other survive, there is some putrefaction there...so, a flaw that was not on the donor may show up anyway.

So:
1) If you select a "bad donor" (something you would not do!) you will get the flaws for the donor oyster's tissue.
2) The donor tissue was PERFECT, but after the grafting operation it just has "bad luck" and the flaws are created there.

 

[pearlescence]

Growing pearls relies on a tiny (usually) around 1mm sliver of donor mantle growing into a maybe 10mm circumference balloon around a nucleus. It's remarkable that it happens without great incident as much as it does.
Incidentally, why such a small piece? Has anyone experimented with bigger? Is 1mm just 'done because that's just how it's done and always was done?

 

[CMN]

Douglas, thank you for your response - very interesting. It seems to me that there is a lot of discussion about pearl blemishes but not much understanding as to the underlying causes. I think it is something that consumers could be better informed about. It could aid in an appreciation of pearls along the entire spectrum of surface quality, from blemished to flawless.

 

[pearlescence]

There isn't much understanding CMN because a lot of the time we simply don't know. It's the same with pearl colour. Why do pearls have colour at all? It's dark where they live usually, they don't need to look fancy to pull a hot mate.

 

[lisa c]

Wendy, lol!
Whispers the missus come see my bissus,
she hopes the Earl won’t see her pearl...

(I’ve been reading about the Earl Buckingham, and his appetites/enormous appreciation of life’s bounty. I wouldn’t want him to see and consequently lust after any rarity or pearl in my possession. My lines are a little too opaque)

 

[CortezPearls]

Growing pearls relies on a tiny (usually) around 1mm sliver of donor mantle growing into a maybe 10mm circumference balloon around a nucleus. It's remarkable that it happens without great incident as much as it does.
Incidentally, why such a small piece? Has anyone experimented with bigger? Is 1mm just 'done because that's just how it's done and always was done?

A lot of experiments have been done over the years about mantle size. Mikimoto actually had a technique where he fully wrapped the bead in mantle tissue! Then smaller amounts were used until it was decided (due to better results) that a proportion of 1/3 of the size of the bead would be the best size of mantle to use for pearl production. But I always preferred MORE mantle, pieces as large as 7 mm sometimes...of course, using beads as large as 10 mm in diameter.
I always felt that the smaller the tissue, the lesser chance of obtaining a pearl...but the smaller the mantle is, the rounder the pearl shape is.

So, it all depends on the species of animal used, the farm and the technician.

 

[CortezPearls]

Douglas, thank you for your response - very interesting. It seems to me that there is a lot of discussion about pearl blemishes but not much understanding as to the underlying causes. I think it is something that consumers could be better informed about. It could aid in an appreciation of pearls along the entire spectrum of surface quality, from blemished to flawless.

I have always viewed pearls as any other natural product: wood, leather, bone, shell...they come from living organisms, and life is sometimes...hard! And living things will bear the "scars" of life on Earth, and it makes it all Unique. Thing is that people are so used to mass-production that they expect the same of things that are simply unique! Heck! The old Latin name for pearl is Unios and that is where we get the modern word "Unique".
We just should know better...but we've been spoiled by mass produced goods.

 

[CortezPearls]

Wendy, lol!
Whispers the missus come see my bissus,
she hopes the Earl won’t see her pearl...

LOL!
That is a Venerid poem of sorts!

 

[CortezPearls]

There isn't much understanding CMN because a lot of the time we simply don't know. It's the same with pearl colour. Why do pearls have colour at all? It's dark where they live usually, they don't need to look fancy to pull a hot mate.

Yes indeed...why would a color-blind creature produce such beautiful colors? It is not enjoying it!
But the crystals do that by themselves, just like a splendid gemstone (ruby, emerald, opal, etc.) is kept hidden inside the ground for ages until discovered by a miner and finally brought to full beauty by a gem-cutter. Why is the gem beautiful??? The earth around it does not recognize it!
In all, we can say all this beauty was made so we Humans could one day ENJOY it. In this we should be THANKFUL to whatever Power made it possible for us to be able to experience the beauty of this world and all in it.

 

[pearlescence]

Yes, but gemstones do not breed and reproduce. Colour is a result of chemistry.

 

[pearlescence]

Pearl in latin is margarita. From which we get Margaritifera margaritifera I am a margaritifera - a seller of pearls.
Unionidae are the general family of bi-valve freshwater mussels

 

[Cees]

Or Margarita is the island in Venezuela where a lot of pearls came from in the past, Wendy?

 

[pearlescence]

Unless the people on the island spoke latin, I think possibly not
https://www.nationalgeographic.com/...3-04/roman-republics-captivation-with-pearls/

https://www.romeandart.eu/en/art-pearls-empresses.html

 

[CortezPearls]

Pearl in latin is margarita. From which we get Margaritifera margaritifera I am a margaritifera - a seller of pearls.
Unionidae are the general family of bi-valve freshwater mussels

Yes, but the Romans recognized the "unicity" of pearls and would refer to them as "unios" as well...the word "margaritari" coming instead from the Greek language, which was very much used at those times.
The name Unionidae basically means "Unique family" or "pearl family" in Latin.

 

[CortezPearls]

Or Margarita is the island in Venezuela where a lot of pearls came from in the past, Wendy?

Both! The Island of "Margarita" in Venezuela is named that way because of the pearls they found there

 

[CortezPearls]

Unless the people on the island spoke latin, I think possibly not
https://www.nationalgeographic.com/...3-04/roman-republics-captivation-with-pearls/

https://www.romeandart.eu/en/art-pearls-empresses.html

Loved the articles...specially the photos of the artifacts and the paintings Thank you!
This part of the 1st article actually gave me something new:

The Romans referred to pearls by the Greek name margarita, and differentiated between various kinds. The largest and most beautiful were called unios; pear-shaped pearls were called elenchi; and when clustered together so that they gently jingled with movement—attracting attention with the noise—they were called crotalia, or castanets.