PSA - Fake Giant Clam Pearls | Tridacna Gigas

jshepherd

Pearl Paradise
Joined
Jun 22, 2004
Messages
6,297
Over the past few years, we've been inundated with images of claims of supposed giant clam pearls, almost all of which come from the Philippines.

This is likely due to a story about a supposed 75-pound pearl (34 kilo) a Filipino fisherman had kept under his bed for a decade.

The story was reported on by NPR, Smithsonian Magazine, Forbes and so many more. Unfortunately, none of these publications vetted the claims made before picking up the story. Any expert could have told them it was not a pearl. It was a piece of shell.

In 2017, SSEF published a Gemmological Brief on fake Tridacna pearls, and specifically included this supposed 34-kilo pearl.

Fake Tridacna Pearl.png

These are not pearls. These are pieces of shell.

fake tridcana 19.jpgfake tridcana 17.jpgfake tridcana 16.jpgfake tridcana 15.jpgfake tridcana 14.jpgfake tridcana 13.jpgfake tridcana 12.jpgfake tridcana 11.jpgfake tridcana 10.JPGfake tridcana 9.jpgfake tridcana 8.jpgfake tridcana 7.jpgfake tridcana 6.jpgfake tridcana 5.jpgfake tridcana 4.jpgfake tridcana 3.jpgfake tridcana 2.pngfake tridcana 1.pngmore fake pearls.jpg

In case you're curious, These are what real Giant Clam pearls look like.











 
They really need to move this on a forum that does Not specialize in pearls. How stupid do they think we are? :-D

Maybe we can just send them a link to Pearls as One as standard if any get through the filter and actually post.
 
Hi everyone,

I have a friend in Palawan Island, Philippines who has a fisherman friend who found a huge pearl weighing almost 4 kilos. They sought for my help where to have this authenticated & be able to sell this eventually.
I need help on this. I can send photos & videos of the huge pearl thru messenger or viber.
Definitely not a scam.

Rex
 
Hi everyone,

I have a friend in Palawan Island, Philippines who has a fisherman friend who found a huge pearl weighing almost 4 kilos. They sought for my help where to have this authenticated & be able to sell this eventually.
I need help on this. I can send photos & videos of the huge pearl thru messenger or viber.
Definitely not a scam.

Rex
I love the: "Definitively not a Scam" line.
 
Who here said: "If you can't wear it, it's not a pearl"? Such a great way to define it.
That works. Although an anklet charm comes to mind for these folks.

In another thread it was shown that the specialized pearl and gemology trades are in basic disagreement over the definition of a pearl. Gemologists believe they must be nacreous, or be relegated to 'calcareous concretion' status. Pearl experts consider either nacreous or non-nacreous products of molluscan pearl sacs to be 'pearls.'

Cleverly, CIBJO avoids providing a definition for 'Pearl', opting simply to regulate terms in commercial usage.

In this landmark 1987 Gems and Gemology (GIA) paper, an in-depth report on Conchs, Pearl appears in quotes (Conch "Pearl") ad nauseum and the authors address the conflicting concepts of "PEARL" in conclusion:

THE TERMINOLOGY ISSUE

Pearls are calcareous concretions that are formed from the shell material and grown naturally in a pearl sac of a molluscan animal (Coomans, 1973). This definition implies that conch "pearls" are indeed true pearls, but that calcareous concretions formed by some other animals (Brachopoda, Vermes, Pisces, Mammalia) are not.

However, most gemology texts emphasize that nacre or orient must be present (Liddicoat, 1981 ; Webster, 1983). By this definition, inasmuch as it is nonnacreous, a conch "pearl" cannot be considered a true pearl.

As can be seen, the calcareous monstrosities from Tridacna Gigas comply with neither definition (grown in a pearl sac and/or nacreous).
 
Relegation to concretion status is odd when several pearl types are elegantly foliated calcite, namely order Pectinidae and most gastropods.

However those are pearls of natural origin. While natural pearl identification is a thing in the labs, the term non-nacreous stemmed from the cultural industry. Even if farms never happened, it would be poor description at best. The roughest pearls are not necessarily entirely calcareous either, having proteinanceous layering. Some species produce both nacreous and calcitic pearls depending on their myostracial onset.

I would define a pearl as a reactive mineralized lesion of mollusks having multiple consecutive layers of periodic growth occluding a nucleus. It's important to use "occlude" to mean hidden, because it implies an object is not cut or reshaped by any means to give the appearance of a pearl.

Although the terminology issue quoted covers two aspects of context, it's still incorrect on the whole. The reason being a shell bead, especially one cut from a nacreous structure could be considered a pearl.

The CIBJO term ought to be more suited to "non-nacreous" than "pearl". In science, non-nacreous is redundant unless specifically applied to a comparasin of pearl structures, not appearance.
 
Relegation to concretion status is odd when several pearl types are elegantly foliated calcite, namely order Pectinidae and most gastropods.

However those are pearls of natural origin. While natural pearl identification is a thing in the labs, the term non-nacreous stemmed from the cultural industry. Even if farms never happened, it would be poor description at best. The roughest pearls are not necessarily entirely calcareous either, having proteinanceous layering. Some species produce both nacreous and calcitic pearls depending on their myostracial onset.

I would define a pearl as a reactive mineralized lesion of mollusks having multiple consecutive layers of periodic growth occluding a nucleus. It's important to use "occlude" to mean hidden, because it implies an object is not cut or reshaped by any means to give the appearance of a pearl.

Although the terminology issue quoted covers two aspects of context, it's still incorrect on the whole. The reason being a shell bead, especially one cut from a nacreous structure could be considered a pearl.

The CIBJO term ought to be more suited to "non-nacreous" than "pearl". In science, non-nacreous is redundant unless specifically applied to a comparasin of pearl structures, not appearance.
I'm just the messenger here. As a current subscriber to International Gem Society I was shocked to see their position but have found it to be an entrenched one, utilizing dated GIA reference (Liddicoat). Your good definition would also allow for pearl blisters, and abalone horns. Nuclei would be excluded as not having been produced in a pearl sac.
 
I'm just the messenger here. As a current subscriber to International Gem Society I was shocked to see their position but have found it to be an entrenched one, utilizing dated GIA reference (Liddicoat). Your good definition would also allow for pearl blisters, and abalone horns. Nuclei would be excluded as not having been produced in a pearl sac.
Yes, "in a sac" narrowed the scope erroneously on several pearl types. Even the term "blister" is too narrow because it encompasses other distinct types. There are three main subgroups... internal, external and a combination of both for onset. Each of these groups can be subdivided into other categories (ie) pallial, extrapallial, myostracial, periostracial and those are subdivided into septic or aseptic groups. The myostracial group may be subdivided into organ types (ie) pallial, intergonadal, endocardial, byssal, adductorial, vestibular, gastric and pancreatic to name a few. Hence at a minimum, there are dozens of pearl types absent in the lab descriptions.

Then we haven't even addressed shape yet. Technically "blister" ought to be limited to describing pearls having angular margins >90 deg to the shell aspect. We have instrusion, protrusion, fused and floating. The entirety can be split into chronic, acute or benign.

All of these subgroups may be classified under two main groups. Modification or displacement. Even those may be split into perforation, strained or obstruction subgroups.

I'm glad you've mentioned these because this includes the proverbial "grain of sand". These are aspetic external/internal extrapallial obstructions when described as fused to the shell. Sand may also infiltrate mantle linings, thus giving rise to aseptic ext/int pallial perforations.

All saltwater cultured pearls are interfascially annexed gonadal periostracial transgrafts. Freshwater are endopallial periostracial transgrafts.

There can be no question there exists hundreds if not thousands of singular or multiple etiological factors which give rise to the onset of pearls.

All this is way over the heads of marketers and consumers, even most farmers, but the labs ought to know better. After all, they are burdened to practice the objective tenets of science. They're relegated to reverse examination of objects removed from their situations. I have the rare, great advantage in my work as I am able to employ a perimortem differential diagnosis to descibe pearls. Too bad it falls on so many deaf ears.
 
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