bead nucleated freshwater : anyone with experience in nacre depth or cracking problem

[pearlsbynature]

Hi All. I'm rather new to looking at bead nucleated pearls, looking at freshwater at the moment and seeing that some have slight fissures in the nacre. Will these fissures later get bigger or even open to become a crack?
The bead nucleated freshwaters seem to be getting much better and bigger, but still can see the bead on many due to, seemingly, the insufficient nacre depth. Should these be avoided entirely?
Can someone please advise on a good way to set the larger/heavier pearls soundly, taking their weight into account? Will glue hold them in a pendant or should they have and screw and/or a supporting wrap? Thanks!

[pearlsbynature]

Maybe these pics will help get a response. The nacre is thick enough, just has these fissures through it. What will eventually be the result? Were they a part of the pearl as it was formed or later created upon pressure or impact? Oh, pearl size is 15mm for smaller, 17-18mm for larger. Thanks!

[lisa c]

_Those are kinda sizable. Are they your pearls or has someone come to ask your opinion about the cracks?

I have some old akoyas that now have cracks like that, but the cracks are my own fault. I wore them every day for over 10 years, and I bought them used/old from an antique shop, in good shape but not superb, dulled by dirt, but no cracks until...

Anyway here's the story - there was a thread on Pearl Guide way back when about restoring yellowed pearls to white again. I tried most of the remedies. One suggested that rehydrating them in the sun was a good idea. The sun warmed the water, and they did look a little better...I took the idea too far, figuring that warmer water = warmer nacre, which would rehydrate faster. I put them in warmer and warmer water until unfortunately, the last time I looked some were cracked.

The nacre expanded more successfully than the bead? or is the bead intact and some of the innermost nacre cracked? At least the surface layer of nacre expanded and contracted without a crack.

1)Not one of my cracked beads has a surface crack, and
2)size of the bead doesn't matter and
3)the cracks are 2 yrs old and haven't spread to the surface. So, that's my result after 2 yrs - but what does it matter since the appearance is unsightly whether or not the crack progresses? Well, any increase in knowledge is of benefit, of course.

I think impact as a cause would show a crack through the outermost layer of nacre. There are a few PGers who've broken pearls deliberately - I hope one of them will take up the thread here, but

- if someone doesn't the topic has probably been addressed in one of the threads on the forums.

I'm going to leave here and check through the archives, but for now you know at least one cause - hot water, no matter how slowly you heat it up.

I'll be checking on the damage that sonic cleaners do next.

In the meantime, though this is very tardy "Welcome to Pearl Guide!", and I hope you've stuck around in spite of the topic not having been taken up. There's a world of knowledge here, and really good people.

Hey, you're already a pearl-guy! and probably already know this stuff! Dang! Don't I feel stupid.
Well, at least you're still here, right? and posting, etc...and you can do your own checking!

[pattye]

Thanks, Lisa, for bringing this thread to our attention. For some reason, it seemed to be showing up as read, until you posted.

I have some hollow flatish keshi that cracked in a similar way during the drilling process. Jeremy thought they were held too tightly in the vice when drilled. I do not drill pearls (yet) so will look forward to others' remarks.

I have dropped many a pearl, and none have ever cracked.

[lisa c]

Hi Pattye! De nada, Dudette! except look how embarrassed I got(grins). Eh, my heart's in the right place.

I remember those, a lovely shade of aqua and the cracks were at the site of the clamps correct? and had a radial-shatter pattern? I must scamper off and check...

My computer isn't loading Pattye's cracked pearls to attachments properly, the arrow just keeps spinning, and it's too late to figure out now.[IMG]Doggawnit!file:///C:/Users/Lisa/Pictures/Pattye's%20cracked%20keishis%20%20IMGP1756_resize. jpg[/IMG]

So, the forum is Consumer Pearl Q & A; thread - Strange Cracks on Keishi Pearls.

I've dropped pearls, too, never cracked one. I've squeezed them in pliers and broken off a chip on an edge. I've scraped layers off with a utility knife, and a diamond nail file. They're pretty hardy, all in all.

[Kevin Canning]

its hard to tell for what might have caused that but in the first picture around the drill hole it does look like the nacre is really thin? It might just be the photograph but when you look down the whole you should see the change from nacre to shell bead - in photo at least it appears to be pretty thin.

That being said if you acquired the pearl with the fissure then there's no way to tell what caused it, pressure, drilling, natural, excess heat or a combination of all.

It does remind me of the experiment Terry did a few years back in this thread: http://www.pearl-guide.com/forum/pea...-bracelet.html

I don't think I would be concerned about the durability of the Tahitian pearls themselves. Generally, Tahitians will stand up to just about anything accept an overly dull drill bit or chemicals (makeup, cologne, etc).

I did a day of testing here at my office a few months ago on the durability of our Tahitian pearls. Here is the gamut of tests and the results:

1.) Drop from a height of 8 ft onto tile. Result: No affect.
2.) Slam in an oak file drawer. Result: Dented the oak.
3.) Propel the pearl at a high velocity and impact the pearl against solid tile. Result: No affect.
4.) Hit the pearl with a hammer against a cement backdrop. Result: Smashed pearl.

When I say "No affect", I mean there were no visible scratches or other visible damage at all. The nacre thickness, measured after finally smashing the pearl, was determined to be approximately 4mm total (2mm per side).

[Cathybear]

I've never drilled a pearls; the only way I've been able to do anything to the nacre involved a hammer and my driveway heh heh. I wasn't game enough to hammer one on the tile floor because I thought I'd break the tile before I broke the pearl. My guess would be the cracks in the top photos ocurred during drilling, but like I said I don't drill, so it is a guess.
Cathy

[lisa c]

Kevin, thank you so much for posting the results of Terry's experiments. Very helpful and informative, and nice to have it right here, right now!

Also, after reading all the science Steve and others have been posting, I no longer believe rehydrating pearls is possible. I'm open to being proven wrong, I just don't know. I did notice peering into the drill hole (after boiling a pearl yesterday) that some of the pearl around the drill hole seemed gritty, and had a wet sandy appearance, and was easier to scrape away. Maybe boiling a pearl after it's been drilled affects it, while boiling an undrilled pearl doesn't.?

[Caitlin]

I missed the part about boiling pearls...tell me why, again? I would imagine it would cook the nacre.......

[lisa c]

Well, Caitlin there's a story behind it (There always is! hee hee. Can you just see it, I'm kicking back and putting my heels up!). The first story was about almost boiling an old akoya necklace (mine) to rehydrate and restore the pearls. They cracked, but the cracks don't penetrate the surface - like pearlsbynatures above.

Story #2 is I bought some poorly dyed pearls from Fire Mt., and posted on PG asking for the fastest way to remove dye. Remember that? I figured trying to remove the dye was worth the effort because they're pretty sizable baroque (by old standards, not new), and shapely!

They weren't the only poorly dyed pearls I bought, but I will say the price was dirt cheap, $1 or so, so I can't and don't fault Fire Mt. I've been experimenting with this second batch because they aren't shapely, they're like horseshoe crabs. I've been scraping the dyed layer off with a box cutter-utility knife, only to discover some really thin but amazing layers of color. You can make some pretty designs with the scraping.

In that pursuit, I accidentally scraped clear a margin between an inner pearl and the outer surface. The two layers separated in my hands, like a turtle and it's shell! The pearl inside was pretty, and shapely, so I've been pursuing this new activity, seeing what I come up with.

Here comes the boiling part. There's a pearl I'm 'disrobing', and the robe won't cooperate! I want to keep the carapace-looking half for something since it's thick and even, and kind of attractive. The pearl inside is nice, and half revealed; at this point it should pop out with a little leverage and it won't. I thought I'd try heating the carapace part of the pearl in boiling water so it would expand and loosen the interface between it and the pearl inside. I put it on a wire and dipped only the carapace part in the boiling water.

As it happened, nothing happened along those lines... the inner pearl got just as hot, seemingly just as fast. I even tried heating the carapace and holding a sock-wrapped icepack on the uncovered part of the inner pearl. Nothing. So then I just threw the whole darn pearl into the boiling water. That's when the interface area got sort of wet and sandy. I didn't boil it for long. Regretting my fit of pique, I fished it out within a minute - or two (grrr, don't make me mad now!). Now, I'm ignoring it for a while, while I think things over. That's it, that's the boiling story.

By the way, neither part of the pearl cracked, so that's another bit to add to our store of information.

p.s. no turtles were abused or amused, or disrobed, for this experiment.
p.s.2 I have no pictures yet, I have yet to learn my camera.

[Marianne]

Thanks for the laugh Lisa. Don't you just love science experiments!
Marianne

[lisa c]

Well, my handle on something-or-other site is clearlypearlcrazy. I should modify it to obsessed! Glad you laughed, because I don't plan these experiments, they just evolve. Wish I could meet you at Ruckus; remember to bring your undrilled pearl for Jeremy?

[KarinK]

Planned or not, Lisa. Thanks for sharing your experiments And thanks for the entertaining way that you share them

- Karin

[lisa c]

Awww, shucks...Thank you for being amused! That gives me a kick!