Iridescence

[knotty panda]

Caitlin: Who are you quoting? Help me find it, please. Thanks!
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Ah, Caitlin, I found it. Interesting discussion. My thoughts turn not toward newly harvested pearls or naturals getting a "face-lift" but towards those pearls under the sea for hundreds of years in the lead box with only sea silt to protect them. Will they need pealing, polishing, etc. to recover their luster and iridescence? Did they lose those attributes? What about color?

 

[Caitlin]

I found this article by mistake, but maybe it is relevent....

 

[CortezPearls]

What exactly have you heard about this? How would it be accomplished? Have you ever known anyone who did this or have you done it?

I am serious about my questions, because we have thought this would be an urban legend as chickens etc have crops which woud prevent any stonelike object from passing through the entire digestive system.

Pearls would get stuck in the crop where the grinding action with tiny rocks and peices of oyster shell etc might polish the pearl but how would the harvester get them out of the crop? And why use a chicken or fowl at all? Isn't that like burning down the house to cook the piglet? Why not just tumble the pearls with bits of oyster shell instead?

A have a book that contains text passages about the old pearl fisheries in the Sea of Cortez, some of the most interesting accounts are said to have come from one of the most famous Pearling entrepreneur: Manuel de Ocio. He was a soldier of Spain, deserted the Navy to fish for pearls here in my State: Sonora. He has "recipes" for "recovering" damaged pearls...this included feeding them to chickens for "peeling", placing the pearls in "cebo de ri?onada de res" (the fat around a cow's kidneys) to improve luster, and a few more. Can't remember them all now...and it was written in olde Caftillian (old Spanish). He never stated "Why" he did what he did.

I am a biologist, so this is what I think:
For birds (chickens/fowl): these birds ingest little stones to help in grinding down food in their stomachs. This grinding plus stomach acid (very gentle, actually) would have been able to do a bit of peeling on a pearl's damaged outer layers.

Cebo de Ri?onada: Fat in this weather quickly becomes oil. Oil can nurture a pearl, give it extra shine and protect it from dehydration.

 

[CortezPearls]

Pearls would get stuck in the crop where the grinding action with tiny rocks and peices of oyster shell etc might polish the pearl but how would the harvester get them out of the crop? And why use a chicken or fowl at all? Isn't that like burning down the house to cook the piglet? Why not just tumble the pearls with bits of oyster shell instead?

Yes, but then again...these are chickens: Food!!! So you kill the chicken, obtain the pearls...make some Chicken Soup for the Pearl Hearted person.

 

[CortezPearls]

A 40x loupe? I better check again. I just haven't really thought I'd see a lot in pearls than in transparent gemstones. I'd probably get more luck in a pteria mabe to see the spirals although I do have unpolished pearls...

Anyway, usually freeform baroques have higher chances to have mind-blowing iridescence. This is just a guess but there maybe the waves in freeform baroques forms an irregular spiral instead of a neat, circullar spiral... there are portions that's more compact than other areas... I hope you get my drift. Wonder what it's like magnifying abolone pearls...

Sorry I forgot to mention I am incredibly MIOPIC. This is like having an incorporated Microscope (which comes really handy when you work with pearls, but at a terrible disadvantage when trying to find a soap bar in your bathtub) so I can SEE more...does anyone else that works with pearls (on this forum) have the same "advantage"?? Have you seen that this is true for you as well?? Maybe a person with normal eyesight needs more help.

And I agree with you: Baroques offer more in the form of iridescence...the surface does act just like the images you have shared with us. Thus, if the spirals are on a bumpy or uneven surface, the more chaotic the interferrence effect.

 

[Caitlin]

For birds (chickens/fowl): these birds ingest little stones to help in grinding down food in their stomachs. This grinding plus stomach acid (very gentle, actually) would have been able to do a bit of peeling on a pearl's damaged outer layers.

So what do you do-kill the chicken to get the pearls out of the crop before the gizzard crumbles them to powder, if indeed they can pass the crop to the gizzard at all?

I have raised chickens, ducks, geese for most of the past 40 some years and stepped in it more times than I care to remember and collected it for compost. I never seen grit of any size come out the other end. It is always a squooshy thick liquid.

We have eaten many of our fowl and clean out the crop as part of it. I find oyster shell and medium pieces of sand 1-2mm or so in the crops. Never even found a marble sized anything in the crop. Why would a pearl pass through the system when the grit won't?
You would have to jam a pearl of any size down the bird's throat because a chicken wouldn't pick up any object larger than the grit size it likes.

Your old pearl maestro ...I do have respect for him, but, I would want to see what his style is in reporting other aspects of pearling before I believe this one. Does he give instructions on how to place the pearl in the chicken and how to retrieve it?

I really think this one is a yard yarn, like some of the stories I've heard the old horse maestro/vacqueros repeat about horses- now that I said that I can't think of an example, but I hope you know what I mean. The ones who tell yarns really like to tell them and a few large fish always seem to creep in......

Honestly if I am wrong, I need to quit belaboring this point, but I really think this one is an urban, er, rural, er, sea story.

 

[Caitlin]

Yes, but then again...these are chickens: Food!!! So you kill the chicken, obtain the pearls...make some Chicken Soup for the Pearl Hearted person.

How many pearls per chicken? It surely can't be an everyday occurance because one necklace worth of pearls would decimate an entire flock unless you put several in each chicken. If you do that, you are grinding pearl against pearl with grit--why put it in the chicken at all?

Nothing personal, I am just taking the view that this is an urban legend and that no one actually has first hand knowledge of using this technique with real pearls in real fowl.

Chickens have crops and gizzards instead of a stomach. What kind of stomach acid does a crop and/or a gizzard produce? I was under the impression they were a sack and a muscle ...... By the time the food is excreted, it is so nitrogenous, it burns plants and should be composted before deliberately applying to plants. I really wonder how a pearl lying in a pile of chicken poop would fare..........

 

[Valeria101]

What kind of stomach acid does a crop and/or a gizzard produce? I was under the impression they were a sack and a muscle ......

Not quite [ you should see my Mam's face while explainig... 'What's that forum of yours about anyway ??!?" ]. And that makes me think that pearls wouldn't survive at all.

So what do you do-kill the chicken to get the pearls out of the crop before the gizzard crumbles them to powder, if indeed they can pass the crop to the gizzard at all?

Your old pearl maestro ...I do have respect for him, but...

The story reminds me a bit about the Spanish chronicles of emerald testing with a hammer (unless that's a legend of a legend too).

I would imagine that only small pearls would get to and stop in the gizzard (like those lil' stones might). But they better be small. And then, they'd get rubbed against smooth pebbles and washed in some acidic juice (Ph 3.6 - 4.4 - apparently) rich with components meant to break down proteins and keratin specifically.

Would imagine that should dig though conchiolin (a keratin, right?) and break the depleted nacre layers... Which starts to make sense, considering those pearls stained by dull, tinted proteinaceous areas. However, MOP is so sensitive to acid, I wonder how much difference the other properties of whatever bio-chemistry involved could make, relative to just dipping pearls in acid and watch them being destroyed

Can't make up my mind whether the respective pearl-treatment was described to encourage competing others to destroy their pearls (as in the emerald story) or what then ???

Keeping in mind that one written document in the 1700s (right? Or.. when do you think this story might have strated?) had about as much impact as the potter books today (relatively, of course). So one could expect effective manipulation with a relatively solly story (unlike today ??!? LOL!).

Just a thought...

 

[CortezPearls]

Really, I don't know most of the answers, because I've never followed those "ole pearler's recipes" anyway. The only one I tried was the "kidney fat"...and it is just like using mineral oil, which is cleaner and doesn't smell bad.
The book doesn't state how many pearls per chicken, nor when to feed it to them (breakfast, lunch or dinner...care for brunch?) nor any other facts...it is like an old recipee book, but written by a Spanish Soldier in the 18th Century. There is also another one on how to bleach pearls and to extract the tiny seed pearls (morralla).

As Caitlin states: it could very well be just another "Pearling Myth" (instead of "Urban/Rural Legend"). To me it kind of makes sense, but I would not risk a good pearl. Maybe with a very bad one...it could be interesting to try it, but I can imagine my children crying because mean old dad wants to kill the poor little chicken for his mean experiments (Yes! Science is a cruel mistress).

At this point we can only try to figure out De Osio's motivations...he is no longer here to answer these questions. His life was cut short when thieves came during the night to steal his pearl treasure, he was not able to pass on his knowledge on pearls. We will probably never know.

 

[pernula]

The story reminds me a bit about the Spanish chronicles of emerald testing with a hammer (unless that's a legend of a legend too).

This was mentioned in Victoria Finley's book "Jewels: A Secret History." I do not remember all the details, but at one point some people did believe emerald was to be hard as diamond. The dealers used this myth to "test" emerald, and when the emerald broke, they were able to claim that it was not real emerald and offered low prices (i.e., they knew the myth to be not true but used that to their advantage). Finley is a good writer and researcher, I would believe her.

This is an aside: there was some discussion of polishing old natural pearls. I really hope whatever money they get out of the pearls and other treasures that was in the sunken ship transporting treasures from South and Central America back to Spain, they would give at least some back to the people of South and Central America. I don't know about the history of that particular ship, but a lot of treasure was taken by force or cunning or unfair prices. It is only fair to give some money back. They need it too.

Just my two cents.

Regards,
pernula

 

[CortezPearls]

Just came back from my vacation. Spent a week in a beautiful, small little colonial town called Alamos...and they had poultry (turkeys, hens, ducks and peackocks) and yes, I tried...and succeded.

Feed the animals a mixture of grain and (reject) keshi pearls (3-5 mm). They ate it all up in a jiffy. No questions asked. I could not perform the second part of the experiment tough Never inspected the faeces either (no time, was just having fun and relaxing).

So: the first part is definitively not hard. I can envision using this method to clean the smaller, lower quality natural pearls...but not for the big ones (larger than 6 mm). Maybe it is the way Manuel de Osio intended. But, as I said before...he is no longer here to answer these questions.

 

[Caitlin]

Well thanks for the gesture. I am currently without any hens for the first time in many years, so I haven't been able to experiment either.

 

[Valeria101]

Resurrecting and old tread with some unusual examples of iridescence in something that isn't nearly close to being a pearl but... but seems to show something close to the 'fish eye' effect so defining of those very, very highly praised black pearls. Of course, 'close' here merely refers to a physical phenomenon - potentially.

I'll add the proper label and link tomorrow. Now, sure you can guess what these things are

 

[knotty panda]

Marbles?

Hmm, it appears the software doesn't like one word answers and I must talk more.

Marbles?

 

[GemGeek]

Only here can we be free to seriously discuss chicken entrails and the "input" of pearls therin. For the pearlized Mexican chickens, it brings new meaning to the saying "it sticks in my craw"

 

[Ashley]

Sorry I forgot to mention I am incredibly MIOPIC. This is like having an incorporated Microscope (which comes really handy when you work with pearls, but at a terrible disadvantage when trying to find a soap bar in your bathtub) so I can SEE more...does anyone else that works with pearls (on this forum) have the same "advantage"?? Have you seen that this is true for you as well?? Maybe a person with normal eyesight needs more help.

I am as well and I find that it's particularly helpful; especially in my old position at ABC Gems where I would sort and grade millimeter or less sized Emeralds, Alexandrites, Sapphires and Rubies, etc. I even requested that my optomestrist temper my ************ contacts to retain my ability to see the teeny details in the stones! I find that trying to set stones or grade their inclusions with my contacts in was doubling my vision and giving me a headache. I tried taking my contacts out before a client came to the office but then you need to wait for your eyes to adjust and so on... so mostly I just left them out

Sorry for throwing the conversation back a couple of frames, but somehow I'd missed this thread previously and am just now able to add my thoughts...

The first page had some absolutely fascinating images- has anybody gotten a chance to flip through Dr. Gubelin's photo atlas of gemstone inclusions?

http://photoatlas.microworldofgems.com/

 

[Ashley]

Valeria

Those are some very pretty glass balls! I dont' know if I should call them marbles (isn't that what marbles are- glass balls?)

I really like the way the light penetrates the upper layers of color and allows us to see inside.

 

[Valeria101]

Glass, right!... translucent, natural... the granulation and internal structure dictate color in Rainbow Obsidian spheres

LINK to source at Mineralminers

 

[knotty panda]

What do I win?

 

[knotty panda]

My sister-in-law sent me this picture this evening of a Rainbow Fire. I can't download it, but I'm sure Valeria can! She can do anything! It's an amazing photo.

http://www.snopes.com/photos/natural/firerainbow.asp