Pearl Production

For those who are unfamiliar with the production levels of pearls, here’s some helpful information. You see, there are three types of pearl nucleation; there’s bead-nucleation and there’s spherical bead-nucleation, which account for the minority of pearl production. There’s tissue-nucleation, which represents the majority of Chinese pearl production. On the whole, the tissue-nucleation method represents most of the 1500 metric tons of of freshwater pearls coming from China! That’s a lot of pearls, folks.

What’s even more interesting is that jewelry can be created from about half of that amount, which is about 800 metric tons, according to various sources in 2006. Now that’s a lot of pearls!

Prior to modern pearl harvesting techniques, the levels of pearls were relatively low. When people think of pearl-bearing mussels and oysters, they would naturally think that there’s a single pearl inside. Actually, there’s more than one pearl per mollusk and with modern technology, mollusks can produce anywhere between 24 and 32 pearls each!

With this modern technology, pearl farmers can now control the color, shape, and size of their pearls! That’s pretty cool that, with modern technology, pearls can be customized while still growing in the mollusk! This amazing pearl production process is achieved by implanting tissue pieces (when a foreign object enters the mollusk, it forms layers around it, thus producing a pearl) in the mollusk. Earlier technology had farmers implanting 25 tissue pieces but now, only 12-16 tissue pieces need to be implanted. Next time you put on your pearl necklace, think about the hard work and the process that went in to producing that necklace. Pearl production has truly come a long way!

From one Type of the Mussel to Another

With pearl jewelry, especially jewelry made from freshwater pearls, you want the best value and the best quality for your money. Obviously, no one wants poor quality pearls. Over ten years ago, pearl farmers have switched from working with the cockscomb mussel (cristaria plicata) to the triangle mussel (hyriopsis cumingi) for better freshwater pearl quality. The use of the triangle mussel is well known by Chinese farmers today. Now when you buy freshwater pearl jewelry, you know that you’re getting a better quality of pearls for a good price!

Pond Butterfly Mussel

Speaking of quality freshwater pearls, here’s another nifty pearl production idea that provides quality freshwater pearls for consumers. It involves using another kind of mussel with a rather “buggy” name.

If you’ve ever heard of biwa pearls, you’ll know that they are freshwater pearls from Japan but now they are being produced in China. The name for the mussel that produces these pearls is known as the “pond butterfly mussel.” According to scientific journals and news articles, 30% of freshwater pearl production comes from this mussel. Even though it isn’t native to China, pearl production from this mussel is gaining popularity. Next time you buy your biwa pearls, you can think about the mussel where they came from.

When you think of “hybrid,” you naturally think of cars as there are several of them out on the road these days. However, you wouldn’t think that they’d apply to pearl-producing mussels, but that is the truth. Chinese pearl farmers refer to these as “leisure mussels” since they do not have a scientific name assigned to them because they have been crossbred from other mussels (it’s similar to dog breeding; there’s no scientific name for mutts as opposed to purebreds).

As mentioned, some of the freshwater pearls in China come from the butterfly and triangle mussels. To get a better quality of pearls, pearl farmers have turned to genetics. Freshwater pearls also come from mussels that have been crossbred from the two, aforementioned mussel species. By crossbreeding mussels, the quality of freshwater pearls has improved as well as the pearl output. The biwa, or pond butterfly mussel, has better quality and vitality, which is why it has been chosen to be crossbred. Next time you put on that biwa pearl necklace, you can think about how genetics played a role in producing your pearls!

Pearls Cultured in the “Fireball” Way

Not all pearls are created equal. If you’ve bought pearl jewelry or have sold pearl jewelry, you will know that not all pearls look exactly the same. This is especially true of freshwater pearls. Some of these pearls have been produced by the CBSB method as mentioned earlier (coin-bead/spherical bead). These little pearls have a comet-like appearance due to the formation of a “tail” on one side, hence the name “fireball pearls” (sometimes known as CBSB pearls). The unique thing about these pearls is that they are bead-nucleated as opposed to being nucleated with tissue, as are the majority of freshwater pearls. Their popularity soared after being featured with pearls from triangle-biwa mussel hybrids (like when the popularity of hybrid cars soared when individuals wanted to drive a vehicle that was fuel efficient).

Freshwater Pearls and Bead Nucleation

Normally, one would think that freshwater pearls cannot be nucleated. That is partially true. Unlike their saltwater counterparts, there isn’t enough room to insert a spherical bead for the mantle to be nucleated. These kinds of mussels are not biologically equipped with a gonad anatomy, which makes bead nucleation impossible (the pearls cannot be bead nucleated in the gonads). CBSB pearls must be produced in a different manner. Let’s look further into how they are produced.

The Process for CBSB Production

Let’s talk about how they are produced since most freshwater pearls cannot be produced this way. The coin bead is surrounded by mantle of the mussel that is encasing it. A square-shaped mantle piece measuring 1mm on all sides, one coin bead, and an incision mark start off this process. Workers use 3-year-old triangle mussels to create CBSB pearls while younger mussels that range from 6 months to 1 year are used in traditional freshwater pearl nucleation.

>Because of the uniqueness of these pearls, this process will take some time (after all, Rome wasn’t built in a day). The next stage in this pearl production takes about a year as the coin pearl accumulates nacre while left in the water. Another pearl, known as a keshi pearl, may be created if the mussel is submerged in water after removing the coin pearl. These techniques might be used at the discretion of the pearl farmer.

In this part of the process, we find out how these freshwater pearls get to be bead-nucleated. Spherical beads are used for this purpose. The farmer or pearl worker removes the coin pearl from the mussel after the mussel is five years of age. In place of the coin pearl, there is a pearl sac. This is where the bead is placed in order for the bead nucleation to occur (this technique is similar to producing South Sea cultured pearls or second-graft Tahitian pearls). Since the freshwater mussel has no gonad, the insertion is made in the mantle. You can think of it as artificial insemination for clams.

The end product can vary in size and implanted beads can reach a size up to 12.5mm. In order for the pearl(s) to grow, a year or two may be needed (the longer the pearl stays in the mussel, the bigger it becomes).

The Tail

So you want to know how this pearl gets its “comet tail.” Let’s take a look on how that forms on the CBSB pearl. The tail itself will not develop in these CBSB pearls if healing takes place where the incision was made AND the bead is covered by the sac. The only way for this pearl to develop is if the incision has a void next to it and after the bead has been placed in the vacant sac (this is when the keshi pearl is harvested). Although this is widely considered how the fireball pearl got its tail, some Chinese farmers are still not clear on how it is developed.

The shape and size of the tail may vary from time to time, depending on how much space is allowed for the tail to “grow.” It also depends on the spherical bead as well. The tail is created when the bead doesn’t fit all the way in the sac. Nacre then fills that void. Here’s an example that might help illustrate the process. Take a plastic, grocery bag (or any bag for that matter) and place a small, rubber ball in it. The ball fits in the bag but it does not fill the bag entirely. Now pretend the ball is a spherical bead and the bag is the sac. Since there is so much space to fill, the nacre starts to form around the bead, thus creating a “tail.” Now you know how fireball bead tails are formed!

Giant Clam Beads and Their Origins

CBSB nuclei from these mussels are typically large; they range in diameter from 9 to 12.5mm (now those are some big beads). It’s been said that these pearls come from freshwater mussels. However, this has produced some controversy as to where the mussels. Their shells come from because it is not economically or physically feasible through the nucleation method mentioned just previously.

The origins of these freshwater shells are unclear because Chinese mussel shells normally produce smaller pearls that are about 7mm in diameter. Pearls that are 9 to 12.5mm in size are normally found in freshwater mussels in the U.S.. Such as the washboard mussel (megalonaias nervosa) and the maple leaf mussel (quadrula quadrula). Because of high costs and pricing, Chinese farmers use white and large beads for pearl production. That way, consumers will be paying a reasonable price for a better quality product.

The giant clam (also known as tridacna gigas) has been known to produce larger nuclei in saltwater shells. The origin of this process was discovered after testing laboratory samples.

Mollusks’ Status as an Endangered Species

Currently, China has not signed an international treaty known as Convention on International Trade in Endangered Species of Wild Fauna and Flora (also known as C.I.T.E.S) for the protection of threatened and endangered species whereas many other countries, including the U.S., have signed it. In relation to this, parts of the giant clam itself are not imported because it is near extinction despite the fact that it is a good source of producing quality pearls.

Summary

In short, freshwater pearl formation continues to improve as more innovative and modern technologies and techniques are introduced to pearl farming.  Such as being able to do the impossible by producing freshwater pearls through bead nucleation and by crossbreeding two different mussels to create better quality pearls. This makes China a strong competitor among the other pearl-producing nations in the pearl farming business. Next time you look at that freshwater pearl necklace in the jewelry store, you now know where those pearls might have come from. If you would like to know more, be sure to do a Google search or go to your local library to find out more about freshwater pearls.