Question: How do pearls 'barrel'

[Kathleen Conway]

When I took my mother's 40-year old akoyas to an appraiser, she commented that "older pearls eventually take on a barrel shape", and indeed Mom's were no longer round. My question is, how does this happen? Does it happen to all round pearls?

Thanks!

 

[Caitlin]

I can't answer your question, but 40 years is a long amount of time for akoyas to last without wearing out.

Could you please post a photo of them and a closeup of a barrel shaped pearl?

 

[Mikeyy]

If I had to guess I would say this is not plausible. But then what do I know.

 

[AMc]

Wow- so what the jeweler is basically saying is that pearl crystalline platelets are like panes of glass- the atomic structure is constantly in motion- albeit extremely slow motion that is invisible to the human eye, and eventually - just like very old glass panes that show rippling and thickening at the bottom - the perfect roundness of the pearl gives way to a more elongated, oval shape due to it's rolling on the skin, or resting in a jewelry box... Interesting.

Nope- never heard of it. But I think that's a pretty cool theory!

 

[Mikeyy]

Even with a theory like that I wouldn't see how it would elongate them because it would be gravitational influence that would change the structure. In fact A theory like that would mean that ancient pearls would be flat as a pancake.

 

[la_corsetiere]

My guess, for what is it worth, would be that she's referring to nacre wearing down on the highest point of the pearl around the circumference, but this would assume the pearls are constantly rotating as they are worn (and worn a lot...). Nacre would need to be pretty thick with that much wear for the bead not to show through, too. Just a theory...

 

[la_corsetiere]

I think we might need GemGeek to chime in on this one!

 

[jshepherd]

My guess, for what is it worth, would be that she's referring to nacre wearing down on the highest point of the pearl around the circumference, but this would assume the pearls are constantly rotating as they are worn (and worn a lot...). Nacre would need to be pretty thick with that much wear for the bead not to show through, too. Just a theory...

I agree. I've seen it happen to Tahitian pearls on leather.

 

[pattye]

Sounds a little strange to me--we certainly have seen quite a few photos of older akoyas, none that I recall were noticeably barrel shape. Perhaps some older akoyas were less round because of having more nacre, and more drop shape.
How about some photos, Kathleen?

 

[GemGeek]

My guess, for what is it worth, would be that she's referring to nacre wearing down on the highest point of the pearl around the circumference, but this would assume the pearls are constantly rotating as they are worn (and worn a lot...). Nacre would need to be pretty thick with that much wear for the bead not to show through, too. Just a theory...

This is exactly what happens. The more you wear them and the more acidic your skin is, the faster it happens.

 

[pearlescence]

Sounds t me like she was making it up as she went along. We should start a thread with all the old pearl myths.

 

[Nerida]

Okay, I think this is weird... I am with Jeremy - probably not round to start with?
I have seen lots of old worn akoyas, and they might have lost their nacre, but never their shape.

 

[pearlescence]

Okay,granted that nacre can wear away over time ...would it wear away so much that the pearls become barrel shaped to the non-pearl eye? on some akoyas we are thinking of fractions of a mm here....
I'll accept that mostof us could spot most wear but a non-pearl person....(although I am not discounting the possibility that the appraiser did know his or her pearls)
but the pearls go barrel shape over time like they are still oozy still sounds like a load of hooey - why not say that over time the nacre wears away
my two favourite myths by the way
green pearls are made by sick oysters
the holes are poked in when the pearls are newly hatched
both of these have been told to me a solomn fact....! who knew?

 

[CLICLASP]

It's a long time since I wanted to post this photo, I was remembering it was in my collections of Gem & Gemmology.
I went through all issues I get, and found it in the fall 1993 issue (can still be ordered on their website).
The associated comment says that is it mainly at end of necklace that a dozen of pearls have been eroded at both ends of the strand due to constant contact with the neck, and that necklace did not receive proper care i.e. wiping with a damp cloth after each wearing.
So this appears to be known as from 1993 ... and since 93, we know what to do to prevent it

 

[CLICLASP]

I agree. I've seen it happen to Tahitian pearls on leather.

Do you mean worn on a leather cloth, or strung on a leather cord?
What is worse with leather, in your opinion (or would it be worse with Tahiti pearls) ?

 

[pearlescence]

Not convinced that wiping with cloth will prevent. There are two possible issues here. wearing away due to acids in some people's skin and wearing away due to rubbing
wiping will prevent the first but I would think that this would affect all pearls
as for the second, since it is the minute rubbing which is eroding the nacre - much like millions of footsteps on a stone step will wear it down - then no amount of rubbing will surely stop this...indeed arguable that more rubbing or wiping will only make it worse (in a nano sort of way!)
In any case the appraiser is wrong in that he/she claimed that it happens to all pearls,whick sort of ooze into ellipticals over time

 

[Hanaleimom]

Do you mean worn on a leather cloth, or strung on a leather cord?
What is worse with leather, in your opinion (or would it be worse with Tahiti pearls) ?

My thoughts:

Tahitians worn on leather cord have been around for a long time in French Polynesia. It's the island style. They live and work mostly outdoors. Even worn outside of FP, I am assuming pearl-on-leather cord owners tend to be more casual and wear them daily. The pearls roll freely on the cord, whereas on a strand, the pearls tend to roll less. Therefore, frequently worn plus the rolling lead to more rubbing against the skin, which cause the nacre to be worn down faster than other jewelry style.

 

[Nerida]

Cliclasp - ah, you have shown what I have been thinking.... that any wearing of the central part would not be uniform throughout the strand due to basic physics - with the changing shape of the torso beneath the strand, different areas of the strand would be more prone to wearing of the pearl by contact with the skin. In my thoughts, the central part of the strand would be least likely to be damaged.
Still interesting comments from Kathleen's appraiser - hardly something that happens to 'all old pearls"!

 

[Caitlin]

First off there is never a change in the shape of a shell-nucleated pearl. Shells stay the same shape they came in or were shaped into balls and they stay that way. I sincerely doubt the nacre changes either, except from an outside mechanical action- or we have would have heard about it.


I got out an akoya pearl choker that once belonged to my MiL.It was from Gumps in SF. It is a baroque strand with the larger more round pearls in the front. Then the sides have several barrel shaped pearls, even one skinny dropped shape. There is no sign of wear around the thread or on the surface-though they have lost a lot of luster. I tried to get a photo but my camera lost its charge and I can't find the charger. I'll keep trying.

So, my best guess is that your strand of pearls came that shape and stayed that shape.

(Did your appraiser take the GIA Pearls (or equivalent) course? If not, it is possible that she, like thousands of jewelers, doesn't know much about pearls except recognizing them and having a rough idea of what the current market value is. (Baroques are usually valued less than rounds).

 

[barbie biggs]

I am confused.

I have two pearls with exaggerated barrel shapes. One is an apricot CFW that is about 6-7mm. No question about it's age as I got it from Jeremy. The color is stunning, which is why it's one of my favorites despite being small. I also love the barrel shape.

The second is a Tahitian, also very barrel shaped: dark green with peacock and cherry overtones and about 10mm.

I thought a barrel shaped pearl was sort of 'born' that way. Otherwise it's just damage.

barbie