Foreign contaminants?

[Mervione]

I was reading this in "The Pearl Buying Guide" by Ren?e Newman:

"Blue Pearls

Dark-coloured pearls found in oysters such as the Akoya or silver-lip oysters. The colour is due to foreign contaminants in the nacre or between the nacre and shell bead nucleus unlike black pearls whose colour is an inherent characteristic [sic] of the of the pearl nacre."

And also:

"Naturally-coloured black pearls can also be confused with naturally-coloured "blue pearls". Unlike black pearls whose colour is an inherent characteristic of the pearl nacre, blue pearls derive their colour from foreign contaminants in the nacre itself or between the nacre and the shell bead nucleus. Naturally-coloured, dark Akoya pearls are good examples of "blue pearls". They may be blue, black, gray, or brown. Black pearls and "blue pearls" can look the same but due to difference in the origin of their color, "blue pearls" are worth less. The fact that "blue pearls" might decay or lose their color if holes are drilled through them is another reason for their lower value."

I have a few questions about this:

1. What kind of contaminants are we talking about? I want to know more!
2. "Black pearls and "blue pearls" can look the same ..." I wouldn?t say that akoya/south seas can look anywhere near tahitians, even if they all are blueish. I thought you?d always be able to tell the difference between SS and tahitians (the luster is usually higher on tahitians for example) and between akoyas and tahitians (akoyas are usually much smaller, to start with). Any opinions?
3. So the blue colour in the blue SS and akoyas might lose their intensity? Ugh, please tell me that this book is wrong.

Another question. The book is saying that mabe pearls (not speaking of that penguin oyster pearls now) are grown into the shell of the oyster/mussel/whatever and then when it?s harvested they take the nuclei bead out of the pearl (!!!) and fill it (!!!) with a paste (!!!). This just seem vulgar in my opinion... Is it true? Is that what they do with those beautiful abalone mabes?

Thanks.

 

[effisk]

An interesting article about abalone pearls on this website: http://www.beyars.com/de_abalone.html but nothing about the nuclei being removed.

Here's the answer to your last question: https://www.pearl-guide.com/mabe.shtml

 

[SteveM]

An interesting article about abalone pearls on this website: http://www.beyars.com/de_abalone.html but nothing about the nuclei being removed.

Here's the answer to your last question: https://www.pearl-guide.com/mabe.shtml

That Beyars.com article seems dated (mentions a number of farms, whereas legal and other manipulations have resulted in a virtual monopoly for Eyris Blue). Also it seems to be an early indication of the intent of the NZ cultured assembled blister (mab?) industry to portray its product as 'pearls' in direct confrontation with CIBJO regulations. CIBJO mandates that branded cultured pearl or faux pearl products must include the words 'cultured' or 'faux.' (ie 'Eyris? CULTURED BLISTER Pearls').

On another note, I'm not exactly sure why it's necessary to replace the nucleus with epoxy, given the often micro-thin nacre thickness and risk of breakage. JMarcus??

 

[effisk]

On another note, I'm not exactly sure why it's necessary to replace the nucleus with epoxy, given the often micro-thin nacre thickness and risk of breakage. JMarcus??

They might reuse the nucleus, but the reason that comes to mind is color. If the nacre is micro-thin, you can see the filling through the nacre, and a colored filling can enhance the pearl color.

 

[Pearl Dreams]

"What kind of contaminants are we talking about? I want to know more!"

I've been reading Strack's book (fascinating!) and there were interesting comments about color and luster in the section about American natural pearls (page 247) :

"The origin of the metallic green to bluish green and bronze colors of pearls from Wisconsin has often been debated, and is generally attributed to copper. A number of waterways flow through areas, which are rich in copper ore. Traces of iron and magnesium probably cause red and pink."

And again on the same page:

"Colored pearls may show a metallic lustre, caused by metallic trace elements. Pearls from the Wabash River in Indiana were found to have an astonishingly strong metallic lustre, which was attributed to metal waste from factories in the neighbourhood."

"Contaminants" are what color gemstones, which would otherwise be colorless-- chromium is what colors ruby red, for example-- so the word does not have a negative connotation necessarily (although it does if the source of the metal elements is industrial pollution.)

As the saying goes, "If life gives you lemons, make lemonade". You have to hand it to those mussels-- life gave them pollution, and they made metallic luster.

 

[Mervione]

Excuse me but eww. This must be how the people that frowns upon cultured pearls feels. I guess it?ll just take some time getting used to the idea that mabe pearls are filled with this epoxy thingy.

Pearl dreams:

That?s really nice information, but sad in a way. It?s bad that we like metallic luster so much when it in some cases (not sure about all cases) is because of pollution... Slightly double edged, isn?t it? Is this metallic luster thingy the case with tahitians too? In that book I?m reading it says that they often have a metallic luster, and maybe that?s just because the nature of the pearls and the oyster rather than influences from the water.

Have any farmers trying out putting polluting the water slightly on purpose to get a certain colour or luster?

Does the blue colour in akoyas and SS really get less intensive after a while like I quoted? Like the colours in a conch pearl.

 

[Pearl Dreams]

Mervione,

In that specific case in Indiana there was a link to pollution, but I would not assume metallic luster is usually caused by pollutants. There are elements in rivers and lakes put there by nature-- Strack mentioned the copper ore in the waters in Wisconsin, and magnesium and iron. I would think the same is true in other waters throughout the pearl producing areas of the world.

I know very little about Tahitians (though I plan to learn more in anticipation of buying ) but I believe their color and luster are caused by the mantle tissue of the shell's being black (black-lipped oyster)-- so I assume their color and luster are natural. Same for the golden SS pearls.

But I recall reading somewhere that there is a range of other colors in pearls from South Sea waters-- not just white, black, gray and yellow. I don't know what the thinking is about the cause of those colors.

But as to natural colors and luster of freshwater and Akoya (or any) pearls, I don't know how one could definitely determine how much of a pearl's appearance is caused by factors solely intrinsic to the mollusk versus the waters it lives in-- after all, the mollusk takes in the water. So if there are trace elements of minerals in the water (which could be there naturally) I suppose they could affect the color and luster.

Please remember this is just conjecture on the part of a collector and that I have no expertise. I just like to read!

 

[Caitlin]

The mussel in my picture below (common name:"Bluefer") mostly has that highly colorful, iridescent inside. It produces purple pearls in clean water.

About the summer of 2005, he had a mom write in and tell us that her son stepped on an open shell which had a purple inside and more!-a purple pearl inside, fairly round 5-7mm. He was 16 or so and made a ring and gave it to his girlfriend.

 

[Pearl Dreams]

...Does the blue colour in akoyas and SS really get less intensive after a while like I quoted? Like the colours in a conch pearl.

I'm looking at Strack section on cultured pearls from Japan, page 362, and she says:

"All natural colours of Akoya cultured pearls are not stable to the light and tend to bleach with time."

 

[Pearl Dreams]

That is cool, Caitlin!

I recall seeing your post about this some months ago. Here is a link to the post with your amazing purple shell photo:

https://www.pearl-guide.com/forum/n...-clam-i-eating-quahog-thread-4.html#post18853

That color is to die for!

 

[Nathan Reed]

After I read

"The origin of the metallic green to bluish green and bronze colors of pearls from Wisconsin has often been debated, and is generally attributed to copper. A number of waterways flow through areas, which are rich in copper ore. Traces of iron and magnesium probably cause red and pink."

and

The mussel in my picture below (common name:"Bluefer") mostly has that highly colorful, iridescent inside. It produces purple pearls in clean water.

I started to wonder if the natural chemistry of different mollusc might govern the coloration of the individual species, and waterborne chemicals cause variations from the norm. Just speculating here, anybody know for sure?