I have been a “Pink Floyd” fan ever since my childhood friend’s brother tortured us both with a continuous -high volume- session of the Album “The Wall”. At first we were scared (Faustino’s intentions were to expel us out of the room), but then we became addicted to the music. The scheme did not work for him, but worked nicely for us. One of the albums I came to enjoy in the early 1980’s was “A Nice Pair”…and when you see these giant pearls you’ll have to agree it is a good name for this blog entry.

This summer presented itself with many challenges and opportunities, but also with unique experiences. We had a chance to visit a certain pearl collector, who had recently acquired two incredible natural Gulf of California pearls: one being a huge “Black Lip Oyster” (Pinctada mazatlanica) white pearl, and the other a large drop-shaped “Rainbow Lip Oyster” (Pteria sterna) pearl. As I’ve stated before: both were NATURAL PEARLS. In two decades of working with pearls we had never seen any like these, so we had to share this experience with all of you.

Pearl #1: The Big Yaqui

I gave this pearl this nick-name for a couple of reasons: 1) we were told that the person that obtained the pearl is from a Yaqui community in the southern part of Sonora, and 2) it is BIG!

This silvery-white baroque pearl was produced from a large, probably very old, “Black Lipped Pearl Oyster” that was fished out of the northern part of the coast of Sonora. When we saw this pearl, it had some brown colored protein deposits on the surface (they can be easily removed) and one of those spots even had the shape of a tiny “rainbow lip oyster” baby (spat)! The pearl was examined under long wave UV light to check for fluorescence and it had the typical blue glow of most pearls: just as expected from a Pinctada pearl.

The pearl weighed in at 106 Carats (21.2 grams)…a true solid beauty!…well, once you peel off some of the brown colored protein.

Pearl #2: The Mermen’s Teardrop

Now, as most of you already know (if you’ve been a loyal follower of this blog) the “Rainbow Lipped Pearl Oyster” is not considered to be a large sized oyster, but more of a medium sized animal so it cannot produce a pearl as Huge as the first one…but this pearl was still quite a find! It was fished out by a local diver.

This beautiful baroque drop-shaped pearl (its actual shape is that of a squished drop) weighed in at 15 carats (3 grams), and it was also inspected under long wave UV: it shone with a beautiful dark red color, typical of pearls produced by Pteria sterna.

Final Remarks

Well, we have a new addition to our “Pearl Museum”: an incredible “Rainbow Lip Oyster” shell with a bubbly-looking blister pearl. It is not the blister pearl that makes the shell so special but its size: it measures 12 cm in diameter, and weighs in at 165 grams (just one valve). The largest previous shell we had collected measured 14 cm and has a weight of a mere 44 grams.

What does this mean? That the “heavy” shell is comes from an long-lived animal: the shells of this species thicken (and become heavy) with age. We believe that this species can live to be –at the most- 8 years old, but the vast majority of individuals will die at an age between 5 to 6 years old. So this shell in particular is our “Metuselah” specimen: the oldest “Rainbow Lipped Oyster” we have been able to find (so far).

You may see this –and other shells- in our small museum display that we have next to our jewelry store, featuring many varieties of pearly shells from the world’s oceans, but if you want to see it now just take a look at the following photo:

To the left you see the Pteria sterna shell, and to the right, a big (but not too old) Pinctada mazatlanica shell (measuring 15 cm).

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This is a short entry but I believe it may be of value to some; this entry originates from an email I recieved just a week ago, but we’ve received this type of e-mails several times before… so I will take this opportunity to forward this information to the widest audience possible. The e-mail I recently received comes from the “old continent” and says:

Good morning:

I’m writing from Spain to ask you:

Some time ago I had lunch at a seafood restaurant and I found a pearl inside a clam. It’s small but roundish and pink colored. Does it have any commercial value?

Thank you and kind regards,

Marta

My answer:

Hello Marta,

Interesting discovery… but to know for sure if it is of value we must first have the following information:

1. Was the pearl found in a cooked clam (baked, fried, steamed)? A "cooked pearl” can lose its value because it loses its beauty when damaged by heat.
2. The species that produced the pearl (its proper or scientific name): Most clams do not produce “true pearls” but instead produce "calcareous concretions" which have no real commercial value.
3. Size and weight of the “pearl”: pearls have a greater value after attaining a minimum size (5 mm) or weight (0.5 g); if the weight/size is lesser than this size-weight, then the economic value is not very significant, but: You have have found a pearl! You’re lucky: natural pearls are rare.
4. If the pearl is nice and large enough, you can have a jeweler incorporate it into a ring or pendant, as an "accent" for it.

Greetings from Mexico

Effect of Heat on a Pearl

All pearls have an amount of water content in their chemical composition (usually from 2 to 5%), and this water is important to maintain the integrity of the nacre in the pearl. Pearls are made of concentric layers of this nacre, which in turn is made from flat, hexagonal-shaped crystals of aragonite (a variety of calcium carbonate) which are bound or “glued” toghether by means of a special protein (conchiolin), which keep the layers of aragonite togheter.

If a pearl is overexposed to heat, it will loose some of its moisture and may fracture and may also become dull or opaque… and if any of these things happen, the pearl may lose its value (in whole or in part, depending on the degree of damage).

Pearl-producing species

Most people associate the pearl as a nacreous gem, although with the massive amounts of imitation pearls (faux perles) and processed (bleached) pearls available, many people associate the pearl as a shiny white sphere (with the look of polished marble). But the fact is that pearl oysters and other mollusks with pearly shells produce pearls in the “traditional” sense: nacreous.

But there are those mollusks that do not produce a “pearly shell” and have a shell that looks more like porcelain, and these organisms are said to produce "calcareous concretions" which are basically "non-nacreous pearls". These porcelain-looking “pearls” are made ​​primarily of calcite, another form of calcium carbonate (usually found in marble, limestone, bone, seashells and eggshells).

However, some species of mollusks are capable of producing non-nacreous pearls that have very special features, such as those from the “Lion’s Paw” scallops (Nodipecten subnudosus), various species of snails (including Strombus sp.) or the “Giant Clam” (Tridacna sp)… but these are exceedingly rare.

Thus, it is vital to know the species that produced the "pearl", and you will have an easier way to know if your pearl could have some “real value”… or if will only have a “sentimental value”. In either case you can consider yourself lucky.

Size and Weight of the Pearl

These two indicators are very important to obtain the value of a pearl. Large pearls have always been rare and therefore command a greater value, thus a pearl with size of less than 5 mm in diameter may not have a great price, while one exceeding 8 mm will have a good value. If your pearl is small, it is better to just keep it… but if it exceeds 10 mm (diameter) you may already have something of value (Note: in addition the pearl should be beautiful and not have cracks, size is not everything).

And although a pearl’s weight is related to its size in a very direct way, this is not always true; such is the case of the so called “Gas Giants”. These pearls can reach very interesting sizes (12 mm and up), but they really possess a thin layer of nacre, and inside have a kind of "organic mud", putrid and foul-smelling… not the type of pearl you want to give away or acquire. These pearls usually have a large size and display a low weight.

The Pearl’s Beauty

For us the main attributes to consider in a natural pearl are:

1. Physical Integrity: the pearl does not have any cracks or fractures, that its nacre is intact (undamaged).
2. Size and weight: that its size exceeds 6 mm in diameter and its weight corresponds to its size.
3. Beauty: even if you have the two previous attributes, the pearl must be beautiful. If it is not beautiful it has got to have some exceptional trait that will give it value; such as the gruesome but Huge "Pearl of Allah", or like the pearls of the Nautilus for their unusual spirals and origin.

We have to consider that the person who finds a natural pearl is very fortunate (and by this I refer not to the cultured pearls that are placed inside a farm-raised oyster/mussel, and sold in little cans) and even if their pearl may fail in one or more of these indicators, this does not mean you don’t have something special and unique!

If you’re one of the Lucky few: Enjoy your pearl! And, if you are not one of them: what are you waiting?!?! Go to your favorite seafood place and gulp down a dozen raw clams!!!

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Here we are back again with this topic that I find increasingly interesting, due in part because I have used it as a form of catharsis, allowing me to remember one of the reasons why we started a Pearl Aquaculture project -some 17 years ago- when we were still students at the Guaymas Campus of the Tec de Monterrey. In those days, we first wanted to understand the reasons or logic surrounding the origin of natural pearls and how they are created within the pearl oysters and -of course- there was this previous “knowledge” about the origin of pearls: the mystical, magical, whimsical and musical “grain of sand theory“, which is really just another “pearl myth”.

Another Myth that Afflicts Humanity

It seems that regardless of the time period or place, this sand-grain-to-pearl myth has become very popular: it can be heard almost in any country and language. In my case my grandmother told me, when I was just a child, that pearls grew in an oyster as a result of an irritation caused by a grain of sand, so that there was no better choice for the little animal than to coat the painful and offensive particle with soft layers of nacre. I, of course, assimilated this important information and used it wherever there was an opportunity  –and there were not many I must admit- until it came time to put this theory to the test.

Previous Experiments

From Left to Right: Manue, Enrique & Douglas

Back in 1991, our select group of friends – including Mauricio Atl Tahuilan, Carlos Navarro Serment and Jesús Gutiérrez – had helped us to collect some 70 Pearl oysters to start off our studies on Pearl oyster reproduction and culture. Most of the oysters collected were “Black Lips” (Pinctada mazatlanica) and only a few specimens were “Rainbow Lips” (Pteria sterna), so we use some of these few animals for a very simple experiment: use sand to produce natural pearls. And the result was simply disappointing: we did not obtain a single Pearl. Zero. Zilch. Nothing. Nada. And there arose the question of why didn’t it work? Because we all know that a grain of sand will induce the production of a pearl…thus, a thousand grains of sand should be capable of allowing for the production of a thousand pearls and a million grains of sand …well, a million pearls!!! It was just so obvious and foolproof.

But it was not. As much sand as we used, we could not produce pearls. Not a single one. On the other hand, when we took a peek inside our oysters we noticed that the oysters were perfectly clean, without a trace of sand. We could not know -for real- what really happened in those days because we simply did not have the time to sit there -in front of an oyster- for some 24 straight hours. Can you imagine yourself sitting, just watching an animal that -for some people- is as interesting as a rock??? Therefore, we came up with conjectures and hypotheses, but we never quite knew what was truly happening; anyway, we were “satisfied” with our guesses. Many years have passed now since those days, and the technology to help us is now available –and is also inexpensive- to perform these small experiments…and, of course, for the “birth” of this Blog to have the motivation to write and document the experiments.

Experimenting with sand: the Present

We used a small fish tank with clean seawater to introduce two “Rainbow Lipped oysters” into which we had –previously- introduce one and a half tablespoons of sand. We placed a small video camera to take a time-lapse video for the next 18 hours to record what happens to an oyster which has sand inside. The results did not astonish us, and lived up to our expectations.

The Results

After 3 hours in the tank, oysters would quickly open and close their valves, in a movement and launched a “cloud” of sand out of their bodies. This action removed a great proportion of sand from their bodies, but for the next 8 hours the oysters continued to, slowly, releases small “sand packets”. These “sand packets” consist of a sticky mucus that the oyster secretes in order to “bind” or adhere the sand, and thus it is more easy for them to remove the annoying particles. By next morning, the oysters were almost perfectly clean.

While – at first view – the oysters seemed to be clean from sand (we could see the most of the sand laying at the bottom of the tank) an oyster was sacrificed in order to inspect its body thoroughly, and we still managed to find a very small amount of sand inside. Under natural conditions, the oyster would have managed to remove all remaining sand in some additional hours, but here it was necessary to see the “mucus in action”: our video displays how the Oyster uses its mucus to catch some sand particles and helps to eliminate them.

Conclusions

Pearl oysters are perfectly adapted to their natural environment – the ocean – which has an inexhaustible source of sand. Because of this perfect adaptation, these lowly creatures can – very easily – remove every single annoying grain of sand from their bodies; thus, we can discard sand as being able to help produce natural pearls. In my opinion this is highly unlikely.

Thus, we hope that with the information generated by this test and the proofs on video we will help –once and for all- eliminate the false myth of the “grain of sand”. We hope that this myth will not become resurrected –a zombie of its former self- and come back to haunt us in the future… I swear that if I have to listen –once more- the question of “Is it not a grain of sand that makes the pearl?” something very, very bad, will happen …. I’m just joking: I have already been seared in the flesh –and mind and soul- with this question for years and years, so I am certain I will be able to sustain it longer (but try not to put me to the test, please).

A Blister Pearl!

While inspecting the oyster that was sacrificed for the “grain of sand experiment” I found a worm-like mud-blister pearl. Since our last blog-episode was about these pearls, and I already had the camera rigged it was just natural to make this information available for you all. So, I simply used a scalpel to break the mother-of-pearl layer on this “small tunnel” and found a small orange colored worm. It was clearly a drill-worm (genus Polydora). This discovery can be seen in the video as well.

Coming soon

This Blog will continue to have more information of interest to you, but probably this information will become a little more “spaced” in time, since our farming activities become intensified during the winter season and we usually spend more time at the farm than at the office (where I write the Blog).

So please do not despair, I promise more posts in the near future and do continue to visit our Blog and send your comments and suggestions.

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Here we are once more with the intention of sharing information about these beautiful marine gems.  On this occasion will continue with the subject of natural pearls and specifically about how these gems are created in nature.

During the era scientific enlightenment in the late 1800′s, scientists from all over the world were searching to understand how pearl oysters were able of producing pearls, and their discoveries were fascinating.  But some of the first things they discovered at to do with the internal structure of the pearl, since in order to obtain the truth it was necessary to cut open pearls and inspect their core.  And what they found is that pearls are very much like onions, at least structurally.

When an onion is cut in half what we see inside are numerous concentric layers, each stacked on the previous one, and in a similar manner pearls are produced: the original seed that caused the pearl to originate will be found at its core, surrounded by millions of micron thin layers of Aragonite.  Perhaps this is a reason why the ancient Greeks gave the name “Margarita” to the pearl, since this is also the word for “onion” (hence the name “Margaritifera” that was given in early times to many pearl producing mollusks, meaning “pearl bearer”) in that language.

The Inner structure of an Onion (left) and a Natural Pearl (right).

In the above images of an onion and a natural pearl (both cut-in-half) we can see their internal resemblance, and going further into the deeper core we can also appreciate how their core is not round, but with each additional coating of nacre (in the case of the pearl) the shape becomes rounder, softer, although most natural pearls I have personally seen are rarely 100% round, most being baroque and a good proportion of them being semi-baroque in shape (mainly in the shape of buttons, bullets and drops).

But of course we do have several types of natural pearls.  Many don’t look like the image that we have in our brains as being a pearl, but they are nonetheless pearls.  We basically have two major groups of natural pearls: blisters and loose pearls.  Of these two groups we would have subgroups as well.  Let us begin with the pearls that could be considered the most common.

Blister pearls

Perhaps some of the most common natural pearls are those usually referred as blister pearls in English, “ampollas” in Spanish or as “ampulles” in French, and we could even say that these laid the foundation for the eventual production of mabé pearls (also known as blister or half pearls).  These pearls are commonly found formed on the pearl oyster’s shell, as a response from a very active “Bio-terrorist” (usually an animal that actively drills through the oyster’s shell).  The reasons for this active attack on the oyster’s shell are varied and depend on the species that attacks the oyster, blister pearls being the result of the oyster’s defense mechanism against these intruders.

The varieties of organisms that “attack” the oyster’s shell are huge and include animals such as sponges, polychaete worms and drill mussels.  Many of these creatures are not really after the oysters flesh, meaning there not there to actually eat the oyster but that they are actually just looking for a “home” and have been known as “domiciliares” because they usually make their homes inside the oyster’s shell and -unfortunately for the pearl oyster-these actually weaken the shell, making it really brittle and easy to break.  Of course, these “Bioterrorists” will also come in direct contact with the oyster’s flesh and this interaction will almost certainly produce blister pearls.

There’s a variety of sponge known as, usually colored with a bright orange red or yellow with a sticky consistency, which grows on a large variety of shellfish here in the Sea of Cortez, and it seems to have a preference for the black-lipped pearl oyster (Pinctada mazatlanica).  It can cause small lump like blisters, but I have never seen any pretty specimen of pearl caused by this sponge.

Another creature capable of causing blister pearls is the infamous drill mussel or pholids.  These creatures –and here I also have to include the Cliona sponge- are actually filter feeders just like pearl oysters are, so we can be sure that they don’t attack the shell to eat the oyster’s flesh, but they have brittle shells so they need the protection of a hard substance around them.  These little creatures can actually bore stone, wood as well as sea shells.  We have seen numerous blister pearls formed by the attack of these agents, as well as in one loose pearl.  These creatures also have a preference for black-lipped pearl oysters, but may occasionally attack older individuals of the rainbow lipped pearl oyster variety (Pteria sterna).

The group of organisms which we find more interesting in the case of pearl formation of the polychaete worms, mainly those of genus Polydora: slender worms usually with a bright red coloration.  These worms have the capacity to infest pearl oysters to the point of weakening them and causing their death and in the process making the oyster produce numerous “mud blisters”, which may eventually become coated with nacre.

Shell Damage caused by Drill worms and Drill Mussels

Mud Blisters

We have examined several varieties of the so-called mud blisters and in most instances where we have found are the remains of dead drill worms, as well as good quantities of very organic mud.  It would be difficult to fully identify what causes this variety of blister pearl, but I believe that it is safe to say that it is a combination of the worm´s drilling activity and the entrance of mud due to the disappearance of the drill worm.  What caused the drill worm to disappear?  Well, we have also seen large numbers of predatory polychaete worms on the oyster’s shell and these may very well go after the drill worms and kill them, leaving their home vacated.

When removing a mud blister and cutting it in half we usually find a protective coating of protein secreted by the pearl oyster that that helps to coat the organic mud and that is in turn coated with nacre.

Unusual blister pearls

Some very unusual specimens have been found that include other varieties of animals as the cause, these include fish and crustaceans.  Perhaps the most interesting specimen is that of a small fish that was found in the shell of a Mexican black lip pearl oyster that was fished in Baja California during the last days of the 19^th century (this specimen is still kept in the American museum of natural history in New York).  The fish was identified as a “pearl fish” (family Carapidae), which are usually associated with many species of clams and oysters and sea cucumbers (please use this link if you want to see an animated diagram of a pearl fish, if you’re a proctologist you will enjoy this).  And although we have seen these fish inside oysters we have never had the fantastic opportunity of finding a “fish pearl”.

Pearl fish are not parasitic but instead they find shelter within the oyster’s shells.  I believe most oysters would not be offended by the presence of this little fish, but in this particular case may be the little fish died and the oyster preceded to rapidly coat it with pearl or nacre, I don’t believe this could’ve ever happen with a live fish.

Other possible sources for blister pearls

Other organisms that could be turned into pearls -but that I have never seen turned into pearls- are the little shrimp and crabs that are found inside pearl oysters.  The little translucent “pearl shrimp” are also found in many other species of clams, such as pen shells, and are typically found within the large Pinctada oysters. The species we find in the Sea of Cortez is Pontonia margarita, and we can usually find two individuals within an oyster (one male and one female, the male usually being the smaller of the two), this species does not seem to affect the pearl oyster.

Another type of crustacean we have seen inhabiting the oyster’s body is the “pea crab”; these little crabs are somewhat soft and quite clumsy, no wonder they need the protection they find inside an oyster’s shell.  These little crabs have only been reported as found living inside the Australian silver lip pearl oyster (Pinctada maxima), but the Sea of Cortez has a variety that is only found within the rainbow lipped pearl oyster (Pteria sterna) and this will be the first time this will be reported in writing.  The name of this species is still unknown (Pinnotheres sp.) and we usually only find one inside an oyster.  We have seen some crabs causing a disturbance within the oyster that could eventually lead to the production of blister pearls, but we have yet to find a “crab pearl”.

So, what do you think about all the life-forms that depend or use a pearl oyster -in a way or another- for their survival? Life is indeed a web, and if you can save one species you will be offering an “umbrella” of protection for many others…

In our next chapter will continue talking about natural pearls and their possible origins, in the meantime I will continue hunting for additional facts and -of course- searching for more mythical pearls: I can clearly see myself wearing a pea crab pearl pendant.

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This is a subject that we wanted to discuss since quite some time ago, but instead we have been discussing various topics in order to be able to capture the attention of as many readers as possible, especially since talking and educating about pearls is somewhat complex and requires greater intention. So far, despite the fact that we have already talked about “Pearl culture” and “natural pearls” -such as those once produced by Don Gaston Vivés in Baja California-  (see our entries on this topic) there are still many people who are confused or who have received incorrect information on the subject. We have found that on Spanish language sites –by the way: this Blog is primarily for Spanish language readers, but we do some effort to have an English version in order to be a bit more “universal” -there is from none to very little information on the subject of natural pearls in Spanish on the web, but in English this is not the case (some very good sites on the subject are: Kari pearls and Love to Know 1911), but you can never have enough information, so here we will try to answer all questions or -at the least– will help you to find new questions (not a bad thing per se).

So let us start this fascinating topic of natural pearls. First, we’ll start with a bit of history, we then will examine certain features of pearls and finally talk about how the natural pearls are formed and we do hope we can help to do away with the incredibly popular myth of “pearls are formed with a grain of sand”… I’ll try my best.

History of the discovery of the Pearl

Who discovered the first pearls? When did people begin to show an appreciation for pearls? What are we having for Lunch today? These are probably the questions that many have pondered upon for ages and for which we do not have a fulfilling answer, but let us “travel back in time” to about 10 thousand years ago (and even before that), when human groups in coastal areas or even in areas with rivers began to swim in search of food (notice the importance of question #3?) and under the philosophy of “everything that can be eaten must be eaten” they began to collect pearl oysters and mussels for lunch. Occasionally, they would find a Pearl inside and this could either become a happy moment or a time of huge annoyance… since one hard bite on a pearl can easily cause a dental crack. But let us suppose they did happen to find a “little pearl”: perfect, beautiful like the Moon, or as green as the sea, or able to display rainbow-like flashes or they were able of seeing their face reflected on it… to our ancestors this was Pure Magic. Let’s say that it could have been a good start for the discovery of the Aesthetics.

Now, how did that appreciation and admiration for these small nacreous orbs became an item used as a gem or for personal adornment? Most likely human beings were already using varied “ornaments”: shells, wood, leather, teeth, bones, stones… (it is stated that the oldest pieces of jewelry found are about 100 thousand years old and were made using snail shells, for more information click here) but the Pearl would become the highlight among any other decorative items because it was much more beautiful and would arrive in an “almost ready” state for its use: while almost all other items (corals, gemstones, ivory, etc.) would require many work-hours in order to end up used in an ornament. But the Pearl was a truly a gift of Nature… and had a value-added feature that today is not easily appreciated: its hardness (this topic will be discussed in a future blog delivery).

Adornments similar to those used by our Human Ancestors

Once the Pearl became more and more popular in the taste of our ancestors it also became a “sacred” or “holy” gem, thus many legends and stories about pearls exist and there is not a sacred book that does not include our beloved Gem within its pages, and this also generated many theories about its formation: that its origin it was purely divine, that when angels shed tears these would fall into the sea and became pearls, or that when lightning struck the surface of the ocean pearls would be formed and would fall into the oyster’s gaping mouths (the lightning being produced by the Greek god Zeus), etc., and these ideas eventually evolved up to the this point in civilization  until we  finally arrived to the widely accepted idea that “a grain of sand enters the oyster’s body and irritates the animal unless it coats it up with nacre and thus…becomes Pearl”. How did we ever get this idea? Let us look into this account more closely.

The theory of the Grain of Sand

What is interesting about this idea is that most people consider it as a very logical and sound theory, and so it must be true. Let us analyze this “theory”, step by step:

1. Pearl oysters live in the sea, in shallow coastal areas and are found attached on hard substrate (rocks, reefs, shells of mollusks, etc.), and in these areas there is enough sand for the purpose of “stuffing” the pearl oysters.
2. It is logical to imagine that in a day with appropriate environmental conditions (waves, wind, strong currents) some sand will become suspended in the water and could travel –using sea currents- until some grains of sand find their way into an open oyster.
3. At this point, the oyster is starting to feel irritation from the roughness from the grain of sand and -as a consequence- the oyster will have to defend itself from this “painful foreign body” by secreting a smooth and delicate substance –nacre- around the grain of sand in order to form a soft and delicate pearl… easy, isn’t it?

A "Panamic Black Lipped Pearl Oyster" (Pinctada mazatlanica)

But I am sorry to say that this is not the case and I’ll be emphatic and will just say NO NO and NO!!!! That is simply not true nor accurate. And in fact, we have reliable and accurate scientific information about what actually happens to an Oyster in order for it to produce a Natural Pearl… but for some unknown reason –could it have been a marketing scam? –”the grain of sand theory” is the one that won and it ended up established in the collective conscience of humanity. How can we prove this theory as incorrect?  We have two tools: the first would be using logic and the second one by means of experimentation. Let’s do this step by step.

Using logic

Natural pearls were almost always scarce. Most sources mention obtaining only ONE (1) natural pearl from every 10 thousand slaughtered oysters. One Pearl for every 10 thousand little animals…. But how much sand do we have available at sea? Why so many grains of sand reaching so very few pearl oysters? How come we can’t find many more pearls?

In our experience -from what we have seen by working for over 18 years here in Bacochibampo Bay-  is that water conditions can be severely affected by a change in tides, a swell or due to tropical storms, or even due to strong Northwest winds, and the change can be so severe that sea-water conditions can change from its normal blue-green color to a “caffé latté” (brown) color due to the immense amount of suspended -containing large quantities of sand and mud- sediments. At times like these, the amount of pearls which should be formed definitively has to be huge, simply because of the potential “sand-grains” in the waters. Now, this kind of phenomenon is not uncommon: it happens very often in our location, especially during winter months. That means that any Pearl Oyster in the Bay might receive from just several thousand to millions of grains of sand per week; and keep in mind that if an Oyster can live about between 6 to 16 potential years…this rises to the amount to that of billions of grains of sand = billions of pearls PER OYSTER.

Thus each pearl oyster should be the equivalent of a treasure chest: it is simply a question of diving for one Pearl Oyster in order to obtain sufficient pearls for several necklaces, bracelets, earrings and gift-sets for the whole family and –why not?- even for the pesky neighbors!!! …but, again, this is not the case: only one of every 10 thousand oysters produces a quality Pearl.

If the cause is not sand… then, what causes a natural pearl to form? We’ll talk about this in our next blog delivery…

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Well, although we have not had many direct comments on our blog, we do have a tool that allows us to know how many daily visitors we have, it also tells us which posts have yielded a higher amount of visits and what people are searching for (keywords) before they “land” on our blog and, based on this, we can say that the favorite topic so far is the one about how to distinguish between real pearls (both cultured and natural) and imitation pearls or “faux perles” (such as ” Mallorca Pearls”). Therefore, we will continue discussing this issue and, once again, I invite you to submit your comments.

A New Option: The Pearl’s Drill-Hole

Comparing drill-holes: true pearl vs. imitation pearl

Drill-Holes of various types of fake pearls. Top: 2 “Mallorca” pearls. Center: Philippine SSP imitation pearl and a “Shell pearl” black pearl imitation. Below: Australian SSP imitation “Pearl shell”.

Analyzing Pearl Jewelry:

The gold setting on this pearl does not allow us to examine its drill-hole.

Colorful Mexican baroque pearl necklace: you can appreciate the knots between the pearls as well as some of the drill-holes.

Unfortunately, many freshwater pearl necklaces and bracelets do not have knots between their pearls, and this not because they are not “genuine pearls,” but because their value and quality does not make them worthy using knots. So, whenever possible, do examine the pearl’s drill-hole.

A string of "Mallorca Pearls” where you can see that there are no knots between the so-called-pearls and you can also notice some plastic shavings or “burrs” around the drill hole.

In our next installment we will discuss how to distinguish pearls using their external appearance, especially their color and texture.

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Natural Pearls…this small phrase can mean different things depending on which portion of the food chain you are located in, so it can either mean utter nacreous ecstasy or feverish anger. Whatever your feelings are, every year we have the fortune of finding a few natural pearls within our farm-raised “Rainbow Lipped Pearl Oysters” (Pteria sterna). This quantity varies tremendously depending on environmental conditions (although some people have gone far to suggest that this depends solely on the actions and decisions taken by certain Political Party members…but no, it is certainly not the case) and the way these conditions become more propitious for the development of certain bio-elements (just a fancy word for “little water bugs”) that are normally found in our oceans.

For us, 2007 was an astounding year in Natural Pearl production, whereas 2008 & 2009 were not very productive in yield, but we did find a couple of very exceptional pearls (see “The Virgin’s Pearl” account of this same Blog). This year seems to be more similar to 2007 in pearl yield and quality.

So, before we proceed with the data from this year’s natural pearl harvest, let us watch a short video on natural pearl harvesting (taken from the 2007 natural pearl harvest):

If you paid close attention to the video, you will have noticed that all natural pearls were found inside a thin, semi-translucent membrane that was attached to the oyster’s mantle. This membrane is known as the “pearl sac” and it is where the pearl develops…in the same way a baby would develop inside a womb. A similar “pearl sac” is formed to produce a cultured pearl, but in this case the pearl sac develops inside the oyster’s gonad and due to Human intervention. Thus, when we find a natural pearl it is quite a surprise (similar to when you are told your wife is expecting twins…trust me on this), there is no Human intervention in their production. To notice the differences between the harvest of natural pearls (the video above) and that of cultured pearls you can now watch this other video:

Now that you have seen both videos you can realize how differently these pearls come to see the light of day or are “born unto the world”. Another significant difference between natural and cultured pearls is their size: most naturals we obtain are in a size range between 1 to 7 mm, whereas the smallest cultured pearls we obtain measure 8.3 mm in diameter. But perhaps the most striking difference would be quantity: you always obtain many more cultured pearls than natural pearls.

In a future post we will talk more in detail about how natural pearls are produced: their incidence, what causes them to appear (a grain of sand of course!!! sure…maybe it was a politician that came up with such an answer), but for the moment I just want to post some photos of some of this year’s natural pearls…let us begin!

This “cute” little natural pearl has quite some personality. Measuring 1 cm at its widest, it has the shape of a toon-like tortoise, complete with a little eye.

It is not the prettiest natural pearl we’ve harvested here, but it now belongs into a select group of “unconventional” pearls we’ve found, such as: doves, cats, hearts, aliens (pretty certain it was a so called “Gray“) and the “American Classic”: Mickey Mouse.

The next pearls are much more beautiful, but more “pearl shaped”, and by this I don’t mean “round”. Very few natural pearls we’ve harvested (out of hundreds in our 16+ years of work) have been perfectly round, and those that have this shape are usually very small (less than 2 mm).

Now we have a pair of “good sized” (7 mm diameter) baroque shaped natural pearls, slightly flattened (something quite normal in natural pearls). Their main color is dark so they would be considered “black pearls”…a term that I don’t particularly like because the Gulf of California Pearl is much more colorful. The one to the right has a red-wine coloration (probably Pinot Noir) and the one to the left has a  blue-green-violet coloration.

Now, we have a pair of pearl trios. The first one in sizes around 5 mm in diameter, but I believe they are even more beautiful than the larger ones: truly a case of “Bigger is not necessarily more Beautiful”. And the following trio (in sizes of 3 mm) are even more striking: some pearls even display the much coveted and desired “Fish Eye” effect.

These little pearls have very strong overtones, the one in the center having the most intense “fish eye” effect.

And to wrap it up for today…a beautiful pair of 8 mm natural pearls with very different colors: one is light gray with a strong violet overtone, the other one has a dark electric-blue coloration. One reason why pearls were known as “Unios” in the Latin language of Ancient Romans is because they were clearly unique, distinctive. These natural pearls are truly deserving of such name…but their Gulf of California Cultured Pearl counterparts are just as unique as their famous predecessor…you will not find any “Clonios” around here.

In our next edition: Cortez Keshi Pearls from the 2010 Harvest. See you next week!

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Learning tricks of the trade is something that we have done since we began researching, back in 1993, and this of course not only involves pearl oysters, but their magnificent product: the pearl. But a thing that has always bothered us are “fake pearls” or imitations. For this reason we have come up with this series. Some time ago, back in 2004, Manuel, Enrique and I took several pearls and imitations and filmed a video of their reaction to the famous “flame test”.  Bibliographic sources mentioned that the artificial or false pearls burn on contact with fire, while  real pearls can survive this process without damage or with minor damage. So, are we to just blindly believe in this? Let’s try it and see what happens!!!  And this video was the result of this experimentation. The results surprised us too, but if we obtained important information. So please watch this video first:

Results

We learned several things when “playing with fire.” The first one is that pearls, both authentic and imitation, obey “Murphy’s Law” in the sense that even if they look “OK” to touch they are not: they become extremely hot!  and thus are difficult to manipulate with your fingers right after the 7 seconds under an open flame. So, if you plan to perform this little experiment on your own, use some tweezers and caution to manipulate the pearl. But for now, let’s describe the results, pearl by pearl:

Freshwater Pearl:

The first pearl to undergo the flame test was a freshwater-pearl of Chinese origin. This pearl was submitted to artificial staining to acquire a dark color and it even had a good appearance, since it even had good iridescence. But after only seven seconds under fire we noticed the following changes:

1. The pearl’s drill-hole was severely affected, its nacre becoming almost pulverized, this in effect extended the drilling area (made the drill hole larger). The pearl’s surface was seriously damaged, like the damage caused by the sun and the environment in an oyster shell after about 10 years of exposure.
2. The pearl displayed small cracks in various parts of its surface, which radiate or spread from small “bubbles” that formed in the pearl’s surface. Before the flame was applied, these were non-existent.
3. The pearl lost much of its luster and color, becoming duller and less appealing.

Chinese (Dyed) Freshwater Pearl on the "Flame Test" - Before and after comparison

So we can conclude that artificially colored pearls (or those that have been subject to some types of processing such as bleaching) are more sensitive to fire and can be destroyed with the flame test… but not burned. The ash or soot on the pearl is easily removed with a rag.

Test Results: Not Passed (or 50% passed).

Naturally Colored Cortez Pearl:

Our Pearls are never subjected to any “embellishment” processes; this actually means that they are never polished, nor bleached, nor dyed … so it was not strange that the “flame test” -in the same 7 seconds time-span as that of the Freshwater pearl- had no visible negative effects: we could find no cracks, no little “bubbles”, no change in the pearl’s appearance. What was most striking was to see that it was more difficult to remove the soot from of this pearl. Finally, there was no perceptible change in the of nacre around the pearl’s drill hole, nor in the pearl’s luster or its color.

Test Result: Passed!

Flame Test on Gulf of California Pearl

Imitation pearl: “Shell Pearl”:

Before discussing the results I want to explain something about these imitations. They are the best imitations we have had a chance to see and analyze. Many suggest that “Mallorca pearls” are the best, but we believe these imitations are superior for several reasons:

1. Have a center of ceramic, which gives them a good weight … like a pearl.
2. They have several layers of paint or varnish. Each layer is of characteristics and two of these layers are semi-translucent so give an effect that is added on the base color layer. The final layer is apparently a protective layer and gives the “sheen” or luster to the pearl. Layers of “color”, in green and purple-are printed in a translucent coating using a “newspaper” or dot-matrix style, thus these two colors seem to “float” on top of the jet-black color that coats the ceramic bead. What do I mean by this? Consider using the image below for better understanding.

Comparison of Tahitian Pearl (right) and Black Shell-Pearl (left)

These imitations (for information on their manufacture process, see here) caused a “craze” in the year 2000. In that year, they were successfully introduced into the market through the famous Gem, Watch & Jewelery Fair, and many were misled by these very good imitations. Pearls that were “affected” by these imitations were the Tahitian black pearl and white South Sea Pearls of Australia. As you can see in the photos, it is very easy to confuse these pearls with a naked eye.

"Baby" SSP (left) vs Shell-Pearl (right)

And although they are very good imitations … they do feel fake when you touch them: this is where they just “lost their magic.” Certainly, a high quality pearl is difficult or impossible to imitate, but for most pearls … specially those that are subject to rutinary processing and end up with a uniform look, imitations will be somewhat easy to produce.

Burned Shell-Pearl

Well, let’s get to the results: the “Shell Pearl” required twice the length of time (14 seconds) under the influence of the flame in order to burn in a manner proper for imitations, this due to its protective outer-cover, which protects it from chemical and mechanical damage, and it seems to have a fire retardant effect . However, this outer-coating can become damaged easily (with scratches) and this facilitates the burning of the “pearl”. In the video you can see how this imitation suffers from severe damage on its surface layers and a yellow-colored area affected will be seen on the area affected by heat.

Test Result: Failed!

Cheap Imitation Pearl (Plastic)

This kind of imitation is the one usually found in most economic products, such as in rosaries, small girls “jewelry” and economic bijoux jewelry. In this case the product is made out of plain plastic beads (polyethylene) with a simple paint covering. They are recognized immediately as false by their appearance, for its light weight and the presence of tell-tale “chips” (since these are usually made with molded plastic, they will have these), worthy of any product of very poor quality.

There is really is not worth talking about these imitations … in just 7 seconds under a flame they will burn and light up, we’ll have thick black smoke and the piece will end up as a small mass of molten plastic. The they are are the most fun to burn!!!

Test Result: Failed!

Mallorca or Majorica Pearl:

This is the famous “pearl”, which everyone wants to try with this test. First of all an external analysis: I can tell you that the external texture of these imitations is usually rougher than that of a real pearl. This imitation is quite successful with “Akoya” pearls (produced in Japan and China), since these pearls have little variety of colors (mostly in the white, yellow and cream-beige range) and their shape is almost always round and in sizes from 6 to 9 mm indiameter. Again: the more “clone-like” the pearls become after processing, the easier it is to imitate them.

The “Majorica Pearls” are made with a glass bead that -supposedly- has been made using “real pearl powder”. Even if this were true, it hardly matters because this can never be observed under the coat of paint. The “paint coatings” of these imitations are made using a “special recipe” which includes sardine (fish) scales (using a “special treatment”) which is referred to as “Pearlescence”, and several coats of this varnish are applied to this glass bead, which also must be “baked” or dried using special procedures (including UV light). This matters little after 8 seconds under fire: the layer of varnish is burned and left with a terrible appearance… leaving exposed areas of a white glass bead behind if you try to remove the sooth and carbonized paint.

Majorica Pearl before (top) and after (bottom) the Flame Test

Test Result: Failed!

This video (in Spanish) depicts the manner in which these “faux pearls” are made (and it seems that they are no longer producing these imitations in Mallorca, Spain):

Conclusions:

1. The “Flame Test” can be very destructive on pearls, both with lower quality (processed) pearls and very especially on “faux perles” or pearl imitations.
2. Pearls and Imitations can become Hot after the use of the flame test: handle with caution.
3. Pearls can become damaged with heat and fire: they are organic gems and they have some water in their composition, so do avoid these to ensure for proper care of your pearls.

Coming soon: Demystifying other pearl myths …

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And now we will continue with last month’s story about our visit to ruins of the World’s first pearl farm and we will go and revisit each area step by step.

The Arrival

Our boat came to rest on the beach, but not a sandy beach but more of a rocky beach full of large oval-shaped water tumbled rocks that make walking quite difficult. Any of you that have visited the local beaches of “Las Saladitas” and “Piedras Pintas” in Guaymas will understand what I mean: the rocks just slide from under your feet and may make you fall. Our boat remained in the water, in an area that once had some concrete and rock slabs that were used as a ramp for loading and unloading boats and other aquaculture equipment.

Landing at Isla Espiritu Santo

And it is quite interesting to notice that even tough the ramps are not there anymore (maybe underneath many kilos of rocks there could be something) -or they are simply not noticeable- you can still find indications of their whereabouts thanks to the useful tool known as “Google Earth”. Yes, if you examine the satellite images from Ensenada de San Gabriel you can see some areas -inside the ocean- where some lines are perpendicular to the coastline: one of these being the ramps -they had a lot of use, because they were needed for the farm’s aquaculture operations and to provide food and water to the thousand employees they had on this desolate island.

Google Earth images of the Pearl Farm site

Another thing of interest is that, after almost a Century of abandonment and being exposed to countless hurricanes, you can clearly what is left of masonry work and even of the more modest wooden buildings.

Storage Buildings

Walking to our right (to the west of our landing site), at about some 100 meters from the coastline we found a heavily impacted land area: scarce vegetation, some “Chivato” bushes (Calliandra sp) and “Choya Cactii” (Opuntia sp), a marked difference with the typical Sonoran desert vegetation found in the surrounding area: large columnar cactii -mainly Organ-Pipe catus and Barrel Cactus- and spiny shrubbery. Clearly, this land was compacted for use as sheds, shaded storage area and maybe even for barracks for the farm’s workers.

This small video (part 1) of our visit to the farm may give you better insight:

For the most part, the storage sheds must have been built with commercial wood (which we found in a very deteriorated state, possibly cedar wood) with the roofs being built with palm fronds and/or wood planks. What was stored under these? You can imagine that many were used to house your average tools, such as axes, saws, mallets, etc., one of them must have been a small forge to produce nails and work on chains and cages, some used for living quarters and cooking, but what was the purpose of this unique farm? To produce a valuable commodity: mother-of-pearl shell (MOP). We have fist hand information (from writings by Dr. Vivés himself) that shed some light on this beautiful natural product (plastic became an alternative for MOP shell, thus many nacre/MOP producing regions closed-down).

The MOP produced at this farm came from the farm-raised Black-Lipped Pearl Oysters (Pinctada mazatlanica). The company had 4 different grades (or qualities) for MOP shell. This is the information they provided at the end of the Mexican Revolution as to the value for MOP at the International markets:

1. “Extra” Grade: made up of large shell (over 15 cm in diameter), with very regular/uniform shapes, without spotting nor drill-worm holes.Valued at $1,000 USD per metric ton.
2. “First” Grade: shells with sizes between 9 to 14 cm, without spotting nor holes. Valued at $400 USD/ton.
3. “Second” Grade: mainly small shells (sizes between 7 to 9 cm) and “clean” (no spots nor holes), but also mixed in with larger shells (9-15 cm) but with defects and imperfections. Valued at $200 USD/ton.
4. “Third” Grade: Mainly consisting of broken shells or with shells with considerable damage (spots & holes) in at least 50% of its surface. Valued at less than $100 USD/ton.

We did find evidence of MOP shell mounds throughout the entire area. Most of the shells having suffered from weathering effects. It is hard to say if these shells are all that was left behind after the destruction of the pearl farm in 1914, or if these are more “recent” shells (no older than 30 years) left behind by fishermen that were illegally fishing them for their pearls. The shells are brittle, have a warm coppery color and most of their protein coating (periostracum) has dissapeared…but are still beautiful and shinny.

MOP Shells

MOP shell had a very important economic value before the use of plastic and was used intensively for the manufacture of buttons, jewelry boxes, knife/firearm handles, jewelry (cameos), chess-sets and even for traditional Asian medicine. Several places flourished economically due to this demand: Broome in Australia (using the large Silver Lip Oyster or Pinctada maxima), Muscatine in the United States of America (using many species of pearly mussels) and -of course- La Paz, Mexico.

As a matter of fact, the main economic source for the farm was the production of MOP shell…the pearls were a much welcomed by product: a gift from God or Nature. In those days only natural pearls existed (cultured pearls were in a research stage in Australia and Japan). Some sources state that the quantity of MOP shell that was exported from the Gulf of California (mind you: these figures do not include the shell that remained in Mexico) between the period comprised by the years 1580 and 1857 was of 95,000 metric tons, roughly converted to 277 tons per year. If we converted this volume to monetary value -using a 3rd grade figure- we are talking about $28,000 USD of 1910 (we would have to convert this figure to its present economic value) which is not bad for those days: $101 USD per ton or…

I would personally stick with the “Unskilled wage” indicator… but would really appreciate hearing from others and see if we can come up with a better figure or even for a “real market price” for MOP these days.

Let us try some math here again. This pearl farm (CCCyP ) is said to have had between 8 to 10 million black-lip oysters under culture conditions. Documents from the farm and Dr. Gastón Vivés state that the annual harvest consisted of some 5 million oysters. An average 4 year-old shell measures some 12 cm in diameter and weighs 10 grams and each organism has two of these (=20 grams of MOP per oyster), thus if we extrapolate we will have 200 kilos per thousand oysters, so 1 million oysters might have produced 200,000 kilos and multiplied by 5 we get 1,000 tons of MOP per year. Of course, this information is not accurate because we lack information on the percentage of shell that was discarded due to low-quality (and some other figures that would help have a better price estimate, such as the percentage of their sizes and their grades) but what I want you to NOTICE is how this one farm could have been able to supply the entire export of MOP shell and the domestic market as well, WITHOUT fishing out the local pearl beds.

A pearl farm can indeed have a positive impact on the local environment if managed in a sustainable manner.

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