How do you bleach a f/w pearl?

R

Richard W. Wise

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Ok you gurus how do you do it. The Chinese do it all the time. Someone told me to use bleach others suggest hydrogen peroxide. What is the secret???
 
Ultraviolet light bombardment, along with immersing the pearls in a hydrogen peroxide solution for awhile- a week? Not sure about the time frame.

no bleach- the chemical is way too harsh for the pearls' surface
 
Here's a typical setup for bleaching pearls:
 

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Ok hydrogen peroxide, how long does it take?

I heard one story how Chinese dealers did it in a couple of hours. Well we will take a look this morning and see. Seems like it took only a couple of hours to bleach a mauve pearl to a sort of pink.

Never heard about ultraviolet before. Long or shortwave?
 
It is- that's what I meant by a h-p Solution. From what I understand, it should be a rather weak mixture as Hydrogen Peroxide is also rather harsh. I've been doing a little digging instead of just responding off the top of my head, and this is what I've found out- good luck with your experiments!!

Time length varies between 7 days to a few weeks- a month is about right, but the longer you leave the pearls immersed in the solution, the weaker the crystalline material will get, and will be much more susceptible to daily wear and tear... it is a balance problem (like everything in the gem world!). For better results, make sure the pearls are drilled first, that way the solution will get a chance to penetrate through the layers of nacre and organic material completely so you get more uniform results.

Light- it can be UV (long or short I am not sure), or it can be an intense fluorescent white light (try to get as close to a 'pure' white as possible)- the pearls should remain exposed to the light source for as long as they are submerged in the hp.
 
Ashley said:
Time length varies between 7 days to a few weeks- a month is about right, but the longer you leave the pearls immersed in the solution, the weaker the crystalline material will get, and will be much more susceptible to daily wear and tear... .

The crystalline structure will get weak but not because the peroxide does anything to the crystals. The peroxide eats at the organic protein(conchiolin) which initially gave birth to the crystals(aragonite) and also holds the crystals in certain formations. Without this organic glue, the crystals will clump together like sea salt. Light can no longer bounce around the crystals like before. Best way to destroy delicate orient that I know of.

Slraep
 
So, Richard,

Is this an experiment you are going to share with us? Or publish so we can read later?

Pattye
so many pearls, so little time
 
The crystalline structure will get weak but not because the peroxide does anything to the crystals. The peroxide eats at the organic protein(conchiolin) which initially gave birth to the crystals(aragonite) and also holds the crystals in certain formations. Without this organic glue, the crystals will clump together like sea salt. Light can no longer bounce around the crystals like before. Best way to destroy delicate orient that I know of.

Slraep

Extremely well said. :cool:
 
Ashley and Slraep,

thanks for very interesting and informing posts, I always like to be well informed.
 
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Greetings All,

Sound a fury, where it that coming from? Well an overnight bath in pure h-p with ultraviolet produced some bleaching. The pearls went from mauve to pink losing basically tone. In addition when compared to the control samples they lost luster and overtone as well.

It is actually quite a relief to know, as I had been told, that two hours in an h-p solution won't turn them white. Thanks to Slraep for explaining in advance the effect of the solution on the conchiolin.
 
Hi Richard,

Glad to know the results of your experiment. H-p is likely something I would not be safe with, as I already know how to make a big mess with water and to stay away from fire! (Although I would love to be able to make my own headpins!)

Pattye
so many pearls, so little time
 
Sound a fury, where it that coming from?

It's a soliloquy from Shakespeare's Macbeth (if that's what you were asking. If not... don't mind my craziness):

"She should have died hereafter;
There would have been a time for such a word.
To-morrow, and to-morrow, and to-morrow,
Creeps in this petty pace from day to day
To the last syllable of recorded time,
And all our yesterdays have lighted fools
The way to dusty death. Out, out, brief candle!
Life's but a walking shadow, a poor player
That struts and frets his hour upon the stage
And then is heard no more: it is a tale
Told by an idiot, full of sound and fury,
Signifying nothing."
 
I am familiar with Shakespeare's MacBeth. I was alluding to a comment made by Ashley on the previous page. Sort of a joke.
 
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