Coin Pearl Coating/Treatment Question

[PearlsAndJade.com]

I've placed three photos of coin pearls on the following page. Its a private page on my web site that can only be accessed by using the url below:

http://pearlsandjade.com/category/coinpearlproject

Because of the need for large size photos in order to get the detail, I had to build a page on my site for the pics instead of posting them here.

The pics show a white 12mm coin pearl with part of the nacre stripped off which leaves the shell nucei clearly visible.

I'm told that these pearls have no "coating"; that they have only had a whitening treatment.

I'm not sure what I'm seeing there. It could be piece of .52mm thick nacre, or it could be a very thin nacre with a .52mm coating. I've cut some of these pearls in half, and I've scraped them, and I still can't determine exactly what it is I'm seeing.

There are a lot of pearl experts here, and I'm sure any one of you can tell by the photos what we're looking at.

You can see the photos on the web page above, and post your comments here. It will be greatly appreciated, and educational for all. I can permanently leave the page with pics in place so future members can see them.

Thanks,

Bill

 

[jshepherd]

I have never dealt in coin personally - I have always thought of them as 'beading quality' pearls. So I am not familiar with treatments etc. But, coin pearls are not simply 'tissue' nucleated pearls, so what you are looking at is the nacre coming off the nucleus. But with a depth of only .53 on a freshwater pearl, this seems very thin - again, I am not wholly familiar with coin pearls.

 

[CortezPearls]

Hi Bill,

Seems to me that the brown colored "coating" is actually natural protein based conquiolin...this protein is basically the "cement" between aragonite crystals so it is a normal part of Nacre.

Usually, the first layers of a pearl are not made of Nacre, but of Conquiolin, followed by Calcite and finally Aragonite-Nacre. Since this protein contains water it dehydrates easily...especially if exposed.

It could also be leftover protein of the original mantle tissue used as graft. Some parts can deteriorate and leave behind these portions of protein that eventually help to shape the pearl.

Thanks for sharing the photos and your info. Never dealt with coin pearls before...I also consider most (most, not all) FWPs to be more suitable for Beading.

Douglas

 

[Caitlin]

Douglas' explanation makes sense to me- especially since I have seen what he is talking about on coin and square pearls. Yes, I am a beader and know these pearls well......

Still, I look for ones with smooth surfaces and no tails. I find them inexpensive at the shows ($9-16 per strand) and expensive in any shop- around 39 per strand with tails and nasty surfaces!

Nevertheless, in spite of their lowly standing in the "round and teardrop" pearl community, these are extremely popular pearls with working women. My sister-in-law Louise Williams of Earth's Elegance sells out of these at every trunk show and she makes lots of them. They mix wonderfully with gemstones of all kinds. I was looking for a picture of one of her coin strands. If I can't find one, I'll post a pic of one of mine.

This pic is one of mine- not as fancy as Lulu's- and was taken with a better camera than I had before, but lost detail when I reduced to proper size for the forum. I am having a problem with that with all my photos- help!

 

[PearlsAndJade.com]

Douglas,

Thanks for your detailed description. I thought the brown part was probably the sac that originally covers the irritant, and I believe that is what you are saying when you say that conchiolin is the first layers.

And that confirms for me that the other part, the .53 mm, is the nacre layers.

There are thousands of qualities of coin pearls, and the price naturally goes up with the quality. Most of the coin pearls at wholesale shows will be in the $6 to $20 price range. The reason for that range is the lower cost of carrying inventory; the price points that most show shoppers are looking for; as well as the rarity of the higher quality pearls. But the wholesale price of the highest qualities will be far above that. Some of the higher quality Chinese fw coin pearls that United States Pearl Co sells will range from $35 to $65 wholesale.

Attached are some photos of 12.5 - 13 mm coin pearls (a pink strand and a white strand) that would wholesale for well over $100 (not including the double knotting and the 14k gold clasp with 3 small .02ctw diamonds) but just as a loose strand. However, I've never seen any of this quality at a jewelry show. I brought them back from China.

I managed to get away to spend a couple hours at the Tucson show Thursday morning, and one dealer had a few strands of high quality coin pearls for $155 per strand. They were nice, but not nearly as nice as the ones in these photos.

Some tips on examining coin pearls:

The high placed general lighting (about 4 feet over the booth) at show booths make everything look nice and hides many defects. It makes it extremely difficult to see the problems with any pearl, not just coin pearls.

Many of these coins, like the one that I cut apart, will begin to deteriorate because of small pits in the nacre, and nacre beginning to peel in various spots, and around the drill holes, which will not be noticed in the lighting that the dealers use.

Place a 100 watt bulb equivalent (there are portable daylight type lights for this purpose) about 12 inches or less, depending on your eyesight, from the pearls and examine them. Examine the pearl closely for flaws visible to the naked eye first. Now hold the pearl close under the light and look down on it (sort of like candling, but a little different) With a very thin nacre the coin pearl will now appear to be more brownish in color because you're seeing the shell nuclei. With a thick nacre you won't see this.

One of the many factory tricks is to intersperse these thin nacre pearls within a strand so that they are not easily noticed.

Look at the small pits with a 10x loupe and you'll see that these appear to be small drill holes down into the nacre. Eventually the nacre will most likely peel on back from there.

Especially look around the drill hole area with a loupe and you'll be able to spot where the nacre is already peeling, and will continue to peel.

My photos file size is too large to post here. Each one is 150kb and the maximum size here is 39kb. So I've made a private page on my web site for these if you wish to see them. http://pearlsandjade.com/category/coinpearlspearl_guide

Bill

 

[Caitlin]

Wow!

Now those are jewels!

Thank you for your excellent tips and comments. .53 would be a good amount of nacre on an akoya? It seems a bit thin for a FW though?

The pearls in the necklace posted above cost $6 a strand at a show and are much better quality than any I have ever seen in a bead store or in SF Chinatown or the SF wholesale jewelry district. Even though my pic is blurry, you can see faint rings on some of the surfaces. Generally one side is smoother than the other. Even though this strand has no tails or really rough spots like the worst strands do, it is clearly mediocre compared to yours! And the retail selling price of the finished piece is around $19-29 depending on the venue! The extreme difference in price is because so very few coin pearls turn out without tails or rings. Yours are very rare.

I think your warnings about the lights at the shows are good. Since Luster is my biggest criteria, I take a AA+ luster necklace with me. When I put it next to another strand, I can see if the other strand is better or worse, for luster. If other criteria are important, you must really watch out for those lights!

I went to the Rodeway G&LW show in Tucson yesterday. This show had a lot of retailers buying from some of the wholesalers and reselling the same stuff at double the prices in the same building! I did not see any coin pearls I would buy, now that I know they are nucleated- I found this out in the past 2 months from a Chinese buy I made- I am not going to invest in this style any more. Another problem with coin pearls is they don’t lie flat when you are wearing them, so I haven’t used them much compared to sis-in-law.

I really want solid nacre pearls and I think the Chinese are going to switch more and more to nucleated, though it may actually take years to accomplish. Meanwhile the FW get keep getting better and better - luster, esp.

I saw some large 9+mm button pearls with wonderful luster ($15 per) at the show and some 5mm with mirror-like luster ($6 a strand!!!) - the best luster I have ever seen in a FW (and that includes the marvelous sample strand I got from PP)! If my comparison strand is AA+ then these must be AAA in luster.

 

[KAC]

This pic is one of mine- not as fancy as Lulu's- and was taken with a better camera than I had before, but lost detail when I reduced to proper size for the forum. I am having a problem with that with all my photos- help!

A little off topic, but for your pictures your going to save detail by reducing size in increments rather then making it all in one jump. Also as a standard I always apply a sharpen filter to each image and usually adjust the brightness and contrast - This is assuming your using photoshop to edit your images.

 

[Caitlin]

Thanks- I was wondering whether to reduce in increments or all at once. Thanks for the photoshop tip too. It is not the first time someone on this forum has said to use photo shop to adjust the image. I forgot when I got my new camera. I thought it was supposed to do the work.

 

[KAC]

ya no matter how good the pic turned out - it can always be improved upon in photoshop. Even pics that are taken with a light box can be improved with in photoshop. But an old graphic artist trick is to open the image, apply a sharpen filter and adjust the brightness and contrast then see how things look. For brightness/contrast I find my magic numbers to be 12/12 or 20/20 depending on the image.

 

[pearllover]

electroplated pearls?

electroplated pearls?

I went to the bead store recently and saw some white lustrous pearls from China, they had irredescent properties with a pink overtone. Very pretty for a strand of 9mm FWP at the very low price of only $36 dollars. The owner graciously told me these pearls were electroplated for the luster and the pink overtones, never heard of such a thing! I am going to go to Hong Kong in Feb and will be shopping for FWP and hopefully some Southseas for personal purposes. HOw can make sure I don't get taken with electroplated pearls other than not shop at stalls and only buy from department stores? How can you tell if a pearl is electroplated other than the fact that one might find dye at the drill holes?! HOw long does the electroplating last before it wears off? THank you.

Perplexed Pearl lover

 

[Doug (Integrity Pearls)]

Electroplating? Irradiated?

Electroplating? Irradiated?

I haven't heard the word "electroplated" used much with our pearls, but I often hear of them being "irradiated". One Chinese wholesaler explained it as a 2-step process... 1)Pearls are soaked in dye for a day or two, then 2)Pearls are baked under special light to lock in the color (inside the pearl). I know tje way I describe it doesn't sound very scientific, but I find myself repeating it often to customers. How accurate am I? Would appreciate any insights into the process, and how I should explain it to customers. Thanks!

 

[lzflzflzf]

My coin pearl

My coin pearl

http://search.stores.ebay.com/CHN-S...sooZ1QQfsopZ1QQftsZ2QQsaselZ113708830QQsofpZ0

Coin pearl is one kind of freshwater pearl, BUT coin pearl has some different with normally freshwater pearl, Normally fresh water is has not a core in the freshwater, BUT coin pearl have round core in the freshwater, If no this core, the shape may be not regular round. except round shape coin, Some times coin pearl may be square , rectangle and diamond, The shape is similar the core in the pearl

 

[jshepherd]

So many other online sellers look under-educated for making claims that their perfectly matched lavender or peach pearls are "natural" colored, let alone their "black" ones!

I would agree with you that you will not find any Site selling naturally black freshwater pearls, but lavender and peach do come straight out of the shells as such. They are very common. In fact, many of the 'whites' have more a peach overtone to them before they are bleached.

I have a photo somewhere - harvest day in Zhuji - that shows a huge mound of freshwater harvested pearls. If I can find it (I think it is on my laptop) I will post it here. You will see all the different shades of freshwaters.

 

[Caitlin]

Correction accepted, especially for the "peach". The picture I saw that made me say that had perfectly matched lavender, all the color of lavender gingham checks. The lavender I've seen that I believe to be natural looked more mauve-y. Like the lavender natural fw pearls on your website. I don't know why I said peach because I know that is the main natural color, I think I meant that evenly and brightly colored peach, not the gentle peach that really is natural.

 

[jshepherd]

I have some really interesting colors, actually. The problem is getting enough that match to market a new piece. There are a few things we are trying with them, but we typically return to making multicolor strands...

 

[jshepherd]

The pix from my laptop!

The pix from my laptop!

Can you see all the colors in the pearls? These were harvested the same day.

 

[jshepherd]

Hundreds of thousands of loose pearls.

 

[Caitlin]

I love the way the guy's hands are dug deep into those pearls! What a feeling that must be!

 

[jshepherd]

It sounds more romantic than it actually is. Those pearls are really slimy. They are basically cleaning the 'gunk' of the pearls with that large cloth.

You can see I am holding just a few. Still had to wash my hands.

 

[Caitlin]

Slimy. That must be why they are staying piled up so high