The colours of freshwater pearls

[marionberry]

I'm very sorry if this question is too dumb, but: where does the colour of freshwater pearls stem from? I drilled some peachy-pink pearls myself recently and it seemed that the core was peachy ... so is it really just the colour of the 'template' that's inserted that will define white - peach - lavender etc body colours? Thank you!

 

[pearlsngems]

The color of the piece of mantle tissue that comes from a donor mussel is what determines the color of each pearl. This is also true for Tahitians, Fiji pearls etc.

 

[valeria101]

... where does the colour of freshwater pearls stem from? I drilled some peachy-pink pearls myself recently and it seemed that the core was peachy ...

You could find the same in a natural pearl: the colour would change - season to season, year to year, or otherwise ... In the end, if you cut a thin section through a pearl, or a shell for that matter, you wll see wide-ish bands of slightly different shades of colour.

I have seen allot of this during a couple of years of research on natural pearls [there were a few freshwater cultured-s around too].

The graft does controll the overall range of colour - as @pearlsngems say, but there is allot of variation due to the host (apparently no genetic contribution - EL McGinty 2011, but everything else about the workings of the pearl sac NGF Mamanghkey et al. 2011...)

 

[marionberry]

So interesting! thank you both!

 

[Pearlescence]

There is no genetic connection between host and donor (ie shell in which a cultured pearl grows and the sliver of mantle tissue taken from another shell which the human pearl farmer thinks will make nice pearls because of colour, quality of nacre etc) But obviously the environment plays a part because food supply and water quality will affect the host as the pearl grows inside it.
As to why there is any colour at all - that's a different question and one for which science does not have a full answer at the moment. Why would the inside of shells have such a variety of colours? No reason.

 

[Arkteia]

don't they irradiate brown pearls to achieve the color? (Nothing wrong with it, just interested)

 

[Arkteia]

I'm very sorry if this question is too dumb, but: where does the colour of freshwater pearls stem from? I drilled some peachy-pink pearls myself recently and it seemed that the core was peachy ... so is it really just the colour of the 'template' that's inserted that will define white - peach - lavender etc body colours? Thank you!

What did you use to drill them? I tried manually and spoiled a pearl

 

[NacreLover]

Perhaps you should watch Josh Humbert's talk from last weekend at the ruckus. He explained why he chose the specific donor shells he does for the mantle tissue they contain. He also showed a white south sea strand he just created and how and why they were white. See Kamoka White South sea necklace below.

 

[NacreLover]

 

[marionberry]

What did you use to drill them? I tried manually and spoiled a pearl

I used a diamond drill bit and a drop of water. The hardest part was keeping the pearl fixed in position.

 

[marionberry]

I can see how the overtones and variety of overall appearance is affected by all kinds of factors (e.g. with Tahitians) ... but I'm still not sure I got this right: with freshwater pearls it will be white nucleus = white pearl body, purple nucleus = lavender body, black nucleus = black body? Or is it the same core giving different colours (but then why would my peachy pearls have a peach core)?

 

[Pearlescence]

There is no nucleus in most freshwater pearls. They are grafted/seeded/started with only a 1mm square piece of mantle tissue from another freshwater mussel which has already been harvested and shows shell with good colour.
With all nucleated pearls (some freshwater and all sea pearls) the colour of the nucleus is white-ish as they should be american river mussel to be drillable
So the colour as it comes from the shell is down to genetics and environment. Man steps in to produce most white pearls (bleached, but not white tahits like the Kamoka strand or white south seas) and yes, brown tahitians are usually but not always dyed. There was a craze for chocolate tahitians a few years go with the demand fulfilled by dyeing pearls.
Grey pearls are the irradiated ones. The current craze in pearl opening parties for garish deep dyed 'skittle' pearls harks back about 10 years to early freshwater stocks. I bet some wholesalers have dusted off old stock from forgotten corners with great happiness at some people's consumer gullability.
You do not need a diamond drill bit when drilling pearls but doing it freehand is unwise as you would be unlikely to go straight through and the bit would cause splintering as it comes through on the far side of the pearl - that is why we drill half and half - clean holes

 

[Pearlescence]

Oh, forgot to mention. Blue and green south sea pearls happen when black organic matter gets into the forming pearl under the white or gold nacre. A rather yuck explanation for beauty!

 

[Pearlescence]

There is a list of pigments at play - Stefanos Karampelas did his thesis on these (Google Scholar) ...

Too much to be said about pearl colors !

That article says much what I said (and what Josh also said, from what you report)
My point was, however, there is no discernible Darwinian reason for any shells to have any colour at all

 

[marionberry]

Awesome! I'm learning so much here.

 

[NacreLover]

Correcting my post above. This is a white Tahitian necklace from Kamoka pearls.

 

[Pearlescence]

How does having colour inside your shell help you pass on your genes? It doesn't.

 

[Arkteia]

I assume that since pearls became suddenly affordable, lots of manipulation gets into producing a strand now. I prefer not to even think about it, just because the technology is there and it is not going to leave. I hope I know more about colored stones, but pearls are new to me, and they are such an elusive substance. I started keeping them in "temp strands" and sometimes I have a feeling which ones are colored Chinese just by looking at the strand - among Tahitians, they look unbelievably bright, like on a Christmas tree, and I once bought a string of baroque Tahitians with one pearl, green, that looks too good to be true. At the end of the strand.

I am pretty glad to have different colors to play with, I only hope that the vendors are not overcharging for these funny pieces. I also suspect that overcharging, as always, happens on the "bottom level", i.e., if you sell a pearl that costs 50 cents at 12 dollars it is a higher markup than selling a necklace that should cost 5 K for 18 K. I probably should take a class...

 

[Pearlescence]

Depends what you mean by 'lots of manipulation'
Naturally coloured pearls just get a wash, a quick polish with walnut chips and maybe drilled.
Tahitians are very rarely dyed or manipulated
It's actually quite hard to find dyed pearls now (except the new craze for 'skittles' pearls at those pearl opening party things. There are probably happy wholesalers dusting out some very old stock.

 

[valeria101]

How does having colour inside your shell help you pass on your genes? It doesn't.

Just stayin' alive ...

half-joking

 

[valeria101]

I once bought a string of baroque Tahitians with one pearl, green, that looks too good to be true. At the end of the strand.

A look not unlike NZ Abalone (H. irirs) nacre is possible ... Baffling pearls !

 

[NacreLover]

I do believe the color is determined by the mantle tissue of the donor and where that was on growing on the color band of the shell it was harvested from. If the shell was colored pink, it will influence the color the new pearl will be. Josh Hunbert was talking about it on his talk last weekend and how he does have some influence on the color Tahtian pearls he grows. This information is at the 23 minute point of his 32 minute talk.

 

[Pearlescence]

See post 5 The influence the farmer has is in what mantle tissue is selected as the donor graft material. The mantle tissue carries the genetic material of the donor shell so the farmer looks at the colours in the donor shell to select the colour of pearls he will grow in the graft recipients

 

[Arkteia]

this is how molecular biologists could raise money for grants. Get the support of well-jewelry industry to find out how they could manipulate the genes to get the best pearl color. I am all for it.