Video in Pearls as One and the grain of sand myth

[linda.wald]

I have some comments on the video at the beginning of the Pearls as One course. Please note, I do NOT believe the grain of sand myth for natural pearl formation.

The video is supposed to discredit the 'grain of sand' myth in forming a natural pearl but it looks to me as if it is supporting it! At the beginning of the video, a comment is made that there are a lot of oysters and a whole lot of sand, but natural pearls are very rare. If a grain of sand getting into an oyster shell is how a natural pearl is formed, there should be lots of them. But then the video goes on to show what happens when a lot of sand is put in an oyster. The lesson I get from this part of the video is: oysters are very good at getting sand out of their shells. So, even if sand is getting in all the time (which it probably is), it is getting put out again reasonably promptly. But what if very rarely the oyster can’t get a grain of sand out again, and the grain of sand myth were true? That would explain why natural pearls are very rare. Almost always the oyster can deal with the sand without forming a pearl, but that one in a millionth (or billionth, or trillionth) time it can’t, and we get a natural pearl.

Remember, I do not believe the grain of sand myth. It doesn’t make much sense, and the epithelial cell getting into the body theory does make sense.

Any comments?

 

[Lagoon Island Pearls]

Grains of sand are implicated in natural pearls. I have dozens of examples.

Grains of sand are not used in the culturing process.

In nature, there are numerous ways pearls form. Not all grains of sand result in pearls.

In cultural operations, there are three ways pearls form. Tissue grafts within the connective tissue of gonads and in the mantles of mussels. These two are technically periostracial but in a myostracial surrogate. The other are mabe, which are also periostracial, but in an extrapallial setting. All cultured pearls are periostracial.

Periostracial means any pearl or shell that forms from sectioned or perforated epithelial tissue.

Extrapallial means the space between the outer epithelium and the shell.

Natural pearls may be uniquely myostracial, perisotracial or extrapallial or any combination of the three.

 

[Lagoon Island Pearls]

The term irritant is also incorrectly used. In myostracial or myostracial surrogate pearls, there is no irritation. Epithelial cells do not appear spontaneously in the presence of foreign bodies.

However, a grain of sand entering the extrapallial space may result but does not cause periostracial pearls, but only coincidentally because the process is already ongoing. Even then, it's not so much an irritant as an obstruction.

Let me give you a lay person's example. Lets say we have a bowl. Every day I spray some paint into that bowl. As time goes by, we will build successive layers. The layers represent the concentric layers of a shell or pearl. Next, on one of the days, we sprinkle a few grains of sand in the bowl, then apply consecutive layers of paint. The grains of sand will remain within the matrix having been fixed to the bowl.

I've just given you an extrapallial scenario as it would apply to mollusks.

Now, if we sit with the technician in the graft shed as they insert sectioned epithelial tissue into the connective tissues of the gonad, but put a grain of sand instead. It will not yield a pearl. Why? Because there is no graft tissue present. A cultured pearl is determined by the donor, not the recipient. The recipient as mentioned earlier, is merely a surrogate.

In natural pearls, there's any number of reason why pearls form. For example, an adductor strain may cause pearls to form within muscle tissue. Parasites may enter through the shell into the extrapallial cavity. They may also penetrate the mantle itself, causing the epithelium to perforate, which may cause a pearl to form. Both are periostracial processes. Then, some parasites may infect the blood stream. This may give rise to autoimmune responses and pearls may form spontaneously anywhere in the soft tissues. These are myostracial pearls.

All grafted pearls are not just periostracial, but also homogeneic in origin. Meaning tissues of identical species. In natural pearls, the mantles of shell bearing parasites may continue to grow after death, because the blood of the host keeps the mantle viable (dividing and multiplying of cells)... forming a pearl. This is known as xenogeneic origin. Meaning tissues of different species.