What is the difference betweeb cultured and freshwater?

[Lizzy]

What is the difference between a cultured pearl and a freshwater pearl? I have been looking for a pearl necklace from my daughter, and from my research have decided that I would like to buy her a cultured strand because of the value. But after reading more about pearls I find that freshwater pearls are also considered cultured. What is the difference? One is from the sea and one is from a lake? How can I tell the difference?

[Kenji]

Hi Lizzy,

This is something that actually comes up quite a bit.

Freshwater pearls are indeed cultured pearls. Most of the time, however, when someone is referring to strictly 'cultured pearls' without the proceeding 'freshwater' they are typically referring to Akoya pearls.
The industry is changing, however, as more jewelers are consumers are educating themselves about pearls. I do not think any type of pearl should be referred to as only 'cultured' as this covers all pearls on the market today, including South Sea, Tahitian, Akoya, and freshwater pearls.

The main differences between a freshwater cultured pearl and a saltwater cultured pearl is where they have been cultured, and the nucleation.

Freshwater pearls are mantle nucleated, in other words a piece of the mantle of a sacrificed mollusk is inserted into the the receiving mollusk where the 'nacre' forms around it to produce the pearl. All saltwater pearls, however, which include Akoya, Tahitian, and South Sea, are bead nucleated. A small bead is inserted with the mantle tissue and the nacre forms around the bead.
Freshwater pearls are, of course, cultured in a freshwater environment, like a lake or stream. The other three main varieties are cultured in saltwater.

Pearls cultured in Saltwater are typically much more valuable than those cultured in freshwater and they also typically have a higher shine, luster, and are consistently spherical or nearly so.

Hope this helps!

[The Jewelry Hut]

Hello:

Very Common question! Here is one explanation.

Fresh Water pearls are easily cultivated from fresh water mussels rather than saltwater oysters. They are produced in great abundance, and are therefore generally the most moderately priced of all cultured pearls varieties. Their unique shapes and gentle pastel colors make them perfect gems for those on a budget.

The Jewelry Hut

[Caitlin]

Freshwater pearls are mantle nucleated, in other words a piece of the mantle of a sacrificed mollusk is inserted into the the receiving mollusk where the 'nacre' forms around it to produce the pearl. All saltwater pearls, however, which include Akoya, Tahitian, and South Sea, are bead nucleated. A small bead is inserted with the mantle tissue and the nacre forms around the bead.

How big is the piece of mantle in fw and what happens to it after the pearl is formed, does it rot?

What kind of bead is put in the saltwater oyster? What is it made out of? Do the sizes of bead vary with size of expected pearl? or same size bead with more nacre on some than others?

[jshepherd]

Hi Caitlin,

I loved your story about Bahrain! Great piece of pearl history. I have been dabbling a bit with a book about pearls and their history, so we should speak some time. I would like to add information to your post, but as this is the holiday crunch time I do not have a lot of free time to write.

In response to your questions regarding the mantle tissue in the freshwater pearls, the piece of mantle tissue is very, very small. It is typically cut into a perfect square, as many farmers believe that the more perfect the shape, the better chance of producing a round pearl. The freshwater mussels are nucleated up to 50 times (in the fleshy mantle tissue) and can produce up to 50 pearls after growing for 3-5 years. The tissue is dissolved, and as it is in the center, all remnants are typically drilled out.

Akoya pearls are always nucleated with a bead. This bead is typically made from the freshwater pearl mussel of Mississippi. This shell is used because it is very thick. Many farms also use beads from the 'Giant Clam' shell as well, although this is strongly frowned upon as this is an endangered species, and the composition of the shell is not very suitable as a nucleus.

The size of the nucleus is actually determined by the size of the oyster. This is determined at the moment of nucleus insertion. By purchasing a particular-age lot of oysters the farmer can predetermine what size range of nuclei will be used. This of course enables the farmer to determine the size of pearls produced as well. The size of the pearl is completely determined by the size of the nucleus. The nacre does account for some size, but the range will always be predetermined. Some pearls may have thicker nacre, but rarely more than .5-.75mm, which in circumference will only add 1-1.5mm of size.

I hope this answers your questions!

[Caitlin]

Thanks for your prompt answer! I do understand your holiday crunch and will slow down the volume of my questions.

Now back to FW VS salt. It sounds like the Akoya pearl is mostly clamshell with a thin coat of nacre. How does the quality of the nacre compare in the best of each kind of pearl?

Thanks!

[PearlReef]

You are right. An Akoya pearl is mostly clam shell. The quality of the pearl depends heavily on the depth of the nacre surrounding that piece of shell.

If a strand from Japan, for example, is going to be rated the highest level on the Hanadama scale it must have at least .45mm of nacre surrounding the nucleus. This is considered extremely thick. The average 'jewelry' quality nacre thickness is closer to .3mm. You have to stay away from the strands with .1-.2mm. This is what you will find in low-end jewelry stores and most TV shopping networks going for around $100. These strands will not last you for more than a few months - with continuous wear.

Freshwater pearls are solid nacre. But they lack a lot of the aesthetic qualities of the Akoya pearl - although they are getting much better these years. The freshwaters are almost never perfectly round, and they rarely have the luster of a high-quality Akoya pearl. The fact that each mussel can produce up to 50 at a time, and they are much easier to produce than Akoya pearls ads to the value differential.

Comparing the two of equal qualities, the freshwater will have more real 'pearl', but the value will always go to the Akoya.

www.pearlreef.com

[Caitlin]

Thanks for the answers. Now I am wondering what has happened if anyone has tried nucleating Akoya osyters with rounded freshwater pearls? Then they would be solid nacre with a brilliant "finish"!

This site has some good info not available other places on the web. I have been clicking through to everyone's web pages that I haven't visited before.
I wonder where the smaller pearl 4-6mm finished pieces are?-besides in that dog collar and bracelet I see everywhere-

[Selectraders]

I have never heard of anyone trying to nucleate Akoya pearls with freshwater pearls. I do not believe this would actually work. The composition of the nucleus must be in line with the host oyster, from what I understand (although I could be wrong). But the nuclei are not expensive, and small round pearls would increase the cost of the pearl dramatically. I am sure there are not many farmers who would take that chance.

There has been a lot of talk about using pearls to nucleate freshwater pearls.

I would actually direct your question jshepherd about this topic. He probably knows much more than I.

Michael
www.selectraders.co.uk

[Caitlin]

Hi Michael

Nice web page. You folks who post here are class acts compared to mass auction sites. I think you offer much better quality and honest prices.

I am wedded to the idea of solid nacre pearls. (If you want to know why read my post on Bahraini pearls). I read elsewhere in this forum that some imperfect fw pearls are tumbled 'til round and put back in the fw oysters, (mussels?) And the dear little critters put nacre on top of the rounded pearl.

I can't believe I am original! If I thought of this, others who live, sleep and dream with pearls have too. I'll bet on it!

I think it is a great idea. How expensive could it be if fw growers are doing it?

Also I notice that they put a foreign species clamshell bead and a piece of foreign species mantle into akoya oysters. How irritating could fw nacre be? What is the chemistry of differing nacres?

I am such a newbie. I know fools rush in, etc. but I am now so caught up in this passion for pearls, I think about them everyday. And I plan how to get some. <drools and rubs hands together> I want solid nacre and Akoya finish. How can this be done?

Since the old fashioned real, natural pearls, are not readily available, I think this needs to be remedied with more alternatives.

[jshepherd]

To date I have never heard of anyone trying to nucleate Akoya pearls with freshwater rounded pearls.
Although the idea does sound ideal, Akoya pearls of solid nacre, I do not think it would work very well.
With a finished product, what would it be, freshwater or saltwater? Because the luster of the freshwater pearl after it has been rounded is gone, it would be very similar to the piece of shell that is currently being implanted in Akoya oysters. Remember, nacre is calcium carbonate as is shell, or mother of pearl. It would be like adding the same thing to the process at a monstrous cost. If the pearls did not go through a full culturing cycle they would give the appearance of thin nacre pearls. I am just not sure I see how the benefit would outweigh the cost.
The composition would not be a serious problem, I believe, but I am not sure. There are nuclei which are suitable, and others that are not - but still may create pearls. This is why the tridacna nuclei are such a problem. The shell does not come from the 'pearl mussel' family, and as such is not suitable, yet it is used everyday. In French Polynesia glass beads were once utilized. Of course this did not work, as when the pearls were drilled many of them shattered.
I will keep it in mind to talk to a farmer friend of mine next month in China to ask about freshwater pearls being used. He may know something about it that I do not...

[Caitlin]

Thank you for your pre-holiday answer!

This thread has very informative material re the difference between. fresh and salt water pearls. I have read it and a couple of other threads at least 3 times.

Here is my layman understanding of what has been said in this thread and much of this forum. Please correct me and I will edit.

All commercial pearls are cultured today, mainly because the “real” pearls of the Persian Gulf are not being harvested commercially any more and if they were, the resulting pearls would be worth many thousands of dollars each. Very few people in the world would ever see or wear pearls if these were the only ones available.

Fortunately, the art and trade of cultured pearls brings pearls into the range of billions of people now.

Saltwater pearls are still at the top of the market with over 100 years of experience culturing behind them. If these pearls have a good, thick nacre they will last for generations. Pearl traders still praise the luster of the saltwater as the best available today. Saltwater pearls have a clamshell bead inserted into them, to get them growing nacre. This insert is perfectly round and increases the chances of a perfectly round pearl, though not all are. Saltwater pearl oysters can only support 1 pearl at a time. Thus saltwater pearls are far more rare than freshwater pearls and always will be.

Freshwater pearls have grown on a piece of foreign mussel flesh inserted in their host. Freshwater pearls can grow up to 50 pearls in each shell making them the commoners of the pearl world. The shape of the flesh insert helps shape the pearl and freshwater pearl farmers have exploited this commercially, very well, by producing thousands of tons of specifically shaped freshwater pearls a year. These pearls are inexpensive, pretty, and available by the hank in many kinds of stores and they are great for crafts and designer jewelry. They are actually very much like glass beads in value, commonness, and uses.

BUT they are not like the classic saltwater pearl, which tends to be much rounder. Freshwater pearl growers have worked on roundness and producing fine pearls suitable for necklaces and have made great strides. Even so, freshwater pearls tend to be off round, even in the highest grades. A perfectly round pearl is still very, very rare in freshwater. Although my question about the chemistry differences in salt and fresh pearls’ nacres has not been answered, luster is apparently not as good in freshwater pearls on average. So, actually only a tiny fraction of freshwater pearls out of the gazillion pounds grown each year are round enough, have few enough blemishes, good enough luster, to qualify as fine jewelry. Even so, the finest freshwaters are not considered as fine as the finest saltwaters.

Questions: Luster varies in saltwater pearls. Is the rule the thicker the nacre the better the luster always true? What other factors might affect luster - genetics, environment? and how?

Luster also varies in freshwater pearls, yet they are solid nacre. So, what are the factors producing best fw luster? Is it possible to find fw pearls with luster rivaling good sw?

Please feel free to wait till after the holidays to answer.

[jshepherd]

Caitlin,

It appears as though you have hit every topic on the head. I can see you have been doing your research!

There are a couple of questions at the bottom of your post that remain unanswered. I did see them in December, but I just noticed today that they remain unanswered, so here goes!

Your Question:
Questions: Luster varies in saltwater pearls. Is the rule the thicker the nacre the better the luster always true? What other factors might affect luster - genetics, environment? and how?

This is generally the case. If an Akoya pearl has thin nacre, it is very rare that it will have a high luster. One thing to watch for, however, is a thin-nacre Akoya pearl that has been enhanced to increase the luster. All pearls are cleaned and polished to increase luster, but any type of coating or treatment meant to enhance the luster is just wrong and deceptive.
There are other factors to high luster Akoya pearls. A lot of it is luck. Every harvest has a mix of high and low luster pearls. Only the actual oyster really knows for sure. But some of this luck can be controlled.
Akoya pearls are typically harvested in the winter. This is actually for a very specific reason. The oysters will continue to deposit nacre around the pearl until the pearl is harvested. When the water temperatures are warm the nacre is deposited more quickly. When the water temperatures are cooler the deposits start to slow down. When nacre is deposited more slowly it tends to have a much higher luster. The pearls are harvested in the winter because the top layers of nacre will have a finer luster. Pearls can also be harvested in the spring, but the overall result will not be as fine as that from an earlier harvest.

Your Question:
Luster also varies in freshwater pearls, yet they are solid nacre. So, what are the factors producing best fw luster? Is it possible to find fw pearls with luster rivaling good sw?

Freshwater pearls are more difficult to discuss. There are so many freshwater pearl farms dotting the pearl producing areas of China, and nearly everyone has their own theories regarding why their pearls are/will be the best.

In China there are more than 10 mussel species currently being used to culture freshwater pearls. The two most common are the Hyriopsis cumingi (Triangle Shell) and the Cristaria plicata. In the 1980’s and the early 1990’s the plicata was the favorite for more farmers. This is because this species of mussel can develop cultured pearls much faster than the former. But in the last decade (thank goodness), the drive has finally been for higher quality versus higher quantity. This raised the popularity of the Triangle Shell, as this mussel consistently delivers higher quality crops. Even so, only about 2% of a freshwater pearl crop will be round to near round. This is why there is such an overabundance of baroque, circle, and off-round freshwater pearls. This is why they are so inexpensive as well.

Perfect freshwater pearls with luster and shine equal to a high-quality Akoya strand do exist, but these strands are still rare. I have come across many sellers with hanks for sale, but most of the time they are demanding prices equivalent or above comparable Akoya pearls. This is just not good business for us. When I do find large lots at competitive prices I always grab them. They are very popular with solid-nacre pearl aficionados.

[jshepherd]

I know that this is an old thread, but I thought I would expand a bit on the subject of pearl nuclei.

Nacre can more or less grow on any solid object. Metals such as gold have even been used in the past. Plastic and powder filled resin has even been used. But to have good nuclei four factors are very important:

*The nuclei must have a very similar density to the host mussel near 2.8g/cc.
*The thermal coefficient of expansion of the nucleus must be compatible with pearl nacre. If a material (such as plastic) is used the coefficient is not equal. This can result in nacre cracking and peeling.
*The nuclei must not be too hard so as to cause excessive wear on drill bits. Although this may not seem like a big expense it can be. We only drill South Sea and Tahitian pearls here in our own office (and at times Japanese Akoya pearls), and we go through at least one bit per day. For a farm processing thousands of pearls each day a nuclei that wears a bit twice as fast is an unacceptable expense.
*The nuclei must take a very nice polish, and remain stable over long periods of time.

The color of the nuclei is also very important. One of the reasons shell is used is that it is typically colorless or pure white. This type of nuclei are in highest demand.

[Caitlin]

Thanks for the answers. Now I am wondering what has happened if anyone has tried nucleating Akoya osyters with rounded freshwater pearls? Then they would be solid nacre with a brilliant "finish"!-

WEll, they may not be nucleating Akoyas with tumbled FW pearls, an idea I like so there would be Akoyas with solid nacre, but they are nucleating fw pearls with thinly nacred Akoyas!
http://www.gia.edu/newsroom/issue/27..._details.cfm#3

and
http://www.belpearl.com/july2000.htm
Swiss laboratory proves Kasumiga pearls are nucleated

This process produces the new Kasumiga pearls of great size and luster!

In one of these aerticles it says that FW pearls have 3x the manganese of saltwater pearls so the lab was able to figure out there were two different kinds of nacre in the pearls- .2mm Akoya nacre on the drilled clamshell bead, the whole thing covered with a thick coat of freshwater pearl nacre >5mm on a 9-11mmfinished pearl.

So since I asked about chemical differences between the 2 kinds of pearls, that is a good beginning of an answer.