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.
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:
- 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.
- 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.
- 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…