Non-bead-cultured pearls (NBCP)

[Orient]

For those who like the range of colours in Pinctada margaritifera pearls and would like to see examples of their internal structures too. This may be of interest: https://www.gia.edu/gia-news-research/non-bead-cultured-pearls-from-pinctada-margaritifera

 

[ericw]

So interesting article, Orient! Thank you for sharing.
It shows clearly any nacre discontinuities which can be found inside tahitian pearls, and their relations with shapes. For exemple, the back part of pearls circles seems to match a high organic material concentration, like any drop shape tops, too.
Is there a similar study about nucleated pearls?

 

[Pearl Dreams]

Very interesting article!

Click on photos in article to enlarge them.

 

[GemGeek]

Thank you for sharing. OUTSTANDING!!!

 

[Orient]

"Is there a similar study about nucleated pearls?"

Not that I am aware of, but a search for other possible articles that show something about bead cultured pearls produced this piece: https://www.gia.edu/gia-news-research/pinctada-maculata-bead-cultured-blister-pearls-shells

Figure 9 is the one that is most relevant.

 

[ericw]

"Is there a similar study about nucleated pearls?"

Not that I am aware of, but a search for other possible articles that show something about bead cultured pearls produced this piece: https://www.gia.edu/gia-news-research/pinctada-maculata-bead-cultured-blister-pearls-shells

Figure 9 is the one that is most relevant.

Very good article too, Orient, thank you for sharing.
I am so interested by what's happening inside pearls... And what you are showing us is significant about complexity of pearls growth, especially for every baroque shapes ones.

 

[Orient]

If you are interested in internal structures you will probably like this one I also found on the GIA website ericw: https://www.gia.edu/gems-gemology/spring-2018-gemnews-very-small-akoya-cultured-pearls

I note that there is a thread about very small akoya bead cultured pearls too but will share it here since the small keshi structures are very interesting and this thread started off on the subject of NBCP.

 

[ericw]

Thank you, Orient. Small non-nucleated structures of these Akoya pearls look like tahitian ones. Are like-void parts in Xray full of conchyoline, like seen on tahitian pearls views?

 

[Katbran]

Thank you for this link . Very interesting!

 

[JerseyPearl]

Yes, fascinating article!

 

[Orient]

Thank you, Orient. Small non-nucleated structures of these Akoya pearls look like tahitian ones. Are like-void parts in Xray full of conchyoline, like seen on tahitian pearls views?

I think you would need some of the members here to answer that more accurately for you ericw. Someone like Hisano who likes to cut pearls in half for her designs should be able to answer the query, but I would think that the internal forms are a combination of voids and organic matter such as conchiolin (we have different spellings I see) in the way of thin solid walls within the voids. Figures 15 and 16 in the article also indicate this is so.

 

[ericw]

Yes, Orient, "conchyoline" is a french word.... Sure Hisano has well seen any kinds of internal pearls structures.
It seems these non-nacreus parts inside pearls can contain several organic materials, more or less degraded.
That would be interesting to know why oysters or mussels produce more conchiolin or more nacre. It makes think of tree rings, which are variable with growth conditions.
Maybe farmers know a lot about that, to harvest their pearls at exactly the right time to get better lustre or colours.
I think this control of growth also explains progress of tahitian pearls colours, on the market.
It's interesting to see how nacre is growing to make circles, then, seeing more conchiolin in the back, that explains often dull, even sometimes dust yellow overtones, of nacre inside these circles.

 

[Pareltje]

Great article!

 

[SunSeeker]

Excellent article! Thank you for sharing!